Testing for brake caliper piston retraction
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- čas přidán 27. 06. 2016
- Stripping down a brake caliper, cleaning the components & fitting new seals and pistons is something all mechanics do, some more than others. But understanding how the caliper really works helps to diagnose faults and know what part is really causing the problem...
A true understanding of piston retraction, what effects it, how its achieved & problems associated with too much or too little is often misunderstood.
Whilst rebuilding the 4 Yamaha Viking calipers I decided to make a quick video which will help explain what its all about...
Andy Mechanic! - Auta a dopravní prostředky
This is really good. Finally, a video that explains how and why the pistons extend and retract. Thanks.
i never thought of using air to test like you did. Great tip and demo.
Mate. Thank you for finally explained this. Was scratching my head wondering how piston retraction worked.
Fantastic… just rebuilt my rear brake calliper and was mulling over this exact concern before I test. Brilliantly explained and illustrated. Many Thanks. 👍🏻👍🏻👍🏻
Great explanation of how piston retracting works Andy. I've heard the theory before but seeing it work like that makes it very clear,. Thanks mate
Just the information I was looking for! I have always wondered how much the brake piston actually retracts after letting off the brake pedals. Thanks for posting the video, now I'm ready to work on my front brakes.
Fantastic video...thanks Andy...this is exactly the video I was looking for to understand how much the pistols need to move back in as I have recently rebuilt my calipers on the CBR
You answered several questions about my brake issue with that one demonstration!
professional info, no one else in youtube explaines how the seals work, just fantastic
Great visual on the pistons. I like the tool set up you have, pretty handy.
Just what I needed Brilliant video Andy , got my breaks to fix now I no what to do thanks from the UK .
Andy your brilliant, thanks for sharing, cheers Mate...
Perfect, this was exactly the info that I was seeking on how to fit and test calipers
Wonderful explanation and demo! Thank you!
Awesome demo!
Really helpful. Thanks. Now I know why my brakes are binding and how to check the pistons retract after repairing.
What a great and useful video. Thumbs up.
Thanks so much for this video! 4 sticking reman calipers in a row here. Time to remove and test them like this and rebuild them myself if need be.
Thanks for the retraction explanation, cool
Wow this is awesome! Never seen someone demo the retraction of the piston, I always wondered how far it would retract. The reason I stumbled on this video is because I am trying to find information on how the inside of the integrated parking brake calipers work. I recently installed brake pads on a vehicle and the pistons where VERY tight to turn with the tool. I am trying to learn about how much friction there should be on the square seal with the piston is turning rather than just pushing in and out like the calipers you demo'd. The brakes appeared to work okay after but I'm unsure if I should have replaced these calipers or not.
Wonderful video indeed, keep up the good work.
Well that was a great tip. Cheers
Thank you for the explanation! I was so confused about how brakes are supposed to work. Probably looking at doing a caliper rebuild on this old Honda CN250 soon.
(But first I'll be rebuilding the brake master cylinder)
Excellent demo thank you...👍
Thank You,
I just started working on a bike that has sat for the last 20 years. and I think this is going to help me determine, if I need to rebuild or replace the Caliper.
+DJ Jader Good. That's always the hardest part knowing if the part can be saved or not. Thanks for the feedback. Cheers Andy
Very informative - the square section seal.
this was exactly what i was looking for, what causes the piston to retract. it was the sqaure cut seal
This was a brilliant example thank you
I knew that pistons must be retracting somehow, but had not really thought about it much. It is clear from your video how they do. I watch as I will be overhauling the front callipers on my Trophy soon and di not know if there was a way to see if they were retracting properly.
Great Vid as usual Andy
Thanks Cliff :-)
Wow I wish everyone could explain as good as you! Hahaha
Importance of the two seal inside and outside.. thank you for sharing.. well said (",)
Excellent video, simply explained..many thanks
Thanks for showing this video, nice one
Great explanation, thank you.
great explanations! thanks
Thanks sharing this video, very knowlageable, the best I ever seen
Always wondered about retraction
helped me , cheers
andy
Great video! Thank you.
No problem Jose, pleased you enjoyed it. Cheers Andy
That’s a great help thank you!
Life saver .thanks mate👍🏽
Very informative: )
Brilliant explanation of how they should work well done, could you please explain some seals are tapered & there seems to be a lot of confusion which way the taper should be ie the high part in or outside the bore. Also I appreciate the “land” itself could be tapered but then you don’t have the same dilemma. Thanks for any help. Keep going good stuff.
Only your video states explicitly that pistons should retract by hand, so my caliper needs a rebuild I guess as I need to use a c clamp to compress them. Thank you!
Great tip thanks
thanks for the helpful and informative video. i'm trying to fix front calipers dragging on my gsxr, because it seems like they drag too much, or more compared to my other gsxr's. cheers
Do they drag all the time or only when warmed up?
@@AndyMechanic the calipers drag all the time...especially with the newly installed brake pads. i discovered that the calipers drag less with used brake pads that have around 40-50% pad remaining. would cleaning the pistons with soap and water, but not disassembling the calipers, would that help the pistons retract? cheers
@carreteras101 okay. Just before you strip the calipers just undo the bleed nipple momentarily to check there is no residual line pressure. If after you have done this they stop binding then it's not a puston/seal issue - report back.
If the above test makes no difference then you will need to remove the calipers & pistons to check for corrosion build up behind the grooves where the main seal & dust seal sit in the calipers body. Corrosion causes the seals the clamp the piston excessively which reduces piston retraction. You will need to clean it all out & reassemble.
It will be easier to pop the pistons out with the hydraulic hoses still connected. To do this remove the calipers away from the brake discs, remove the pads. Remove master cylinder cap & fill reservoir. Now insert a steel ruler or just one brake pad. As you pump the brake lever (not too fast) you will see the pistons start ti come out, usually one then the other if more than one per caliper. The ruler or pad will prevent the piston fully exiting the casting - do not allow this to happen until all pistons are as far out as possible.
Once all fully extended you can then disconnect the hydraulic hoses & seal up to prevent the master cylinder draining out (this will help greatly during the bleed up process).
Now with the calipers on the bench you should be able to remove the pistons the last few mm. Do not damage the outside surface of the pistons. If they are corroded at all they must be replaced with new seals.
Remove the seals & inspect the grooves for corrosion - if present then scrape out using a scriber or alike.
Good luck :-)
@@AndyMechanic thank you. i will undo the bleed nipple and report.
Andy, what if the piston is hard to push back in the housing, what could be the issue? The piston goes in easy if the square cut seal is not installed, but once the seal is there, it doesn't go in, and if it goes in, it gets stuck.
Hi Andy!
I’m hoping i can get a reply.
I’ve been experiencing brake issues on my truck, the first pedal goes to the floor always, then after 2-4 pumps, the pedal is firm and the car brake works;
The car has been checked by 3 mechanics without success, all said there is air in the system and had to be bled; also replaced master cylinder but still no improvement.
Could this be caused by a faulty caliper? Should both pistons move in the same time when applying pressure? Is seems that the pads are no flat on the disk, maybe there is too much space/retraction then everytime i apply the brake, the pads need to move too much and that’s the reason why the pedal is soft?
You reply would be greatly appreciated!
Great demonstration. I have probably this problem because everything is moving in my brake but it still smokes on on one side. How do you advise me to treat it
Thank bro 🇯🇲 you just help me out
Thank you so much! Now I know
I have dual piston calipers that only one piston works on front. Trying to determine if calipers need replacing. I bleed the brake line and one side had air in lines.
Thank u!
👍Well done my friend. Thank you
Question my pistons not moving when applying my break pedal even though my breaks calibers are new. What can it be
Awesome Andy, I now know how they retract. I have some very old Wolseley 6/99 pistons that are a little pitted. After cleaning up best I can, they are still too tight in bore, even testing without square seal. Best way of cleaning these up at home? Don't fancy sanding, and while don't have a lathe, don't think metal should come off either.
Hi Tony, that seems very odd indeed? The pistons should move freely with a small amount of clearance to the body. Has the corrosion caused parts of the piston surface to swell increasing diameter a little?
Cheers Andy
@@AndyMechanic Thanks so much for getting back Andy :)
I don't think swell so much as maybe the pitting needs more thorough treatment - but what method?
I''ve just used a Scotch Brite on piston at mo as wasn't sure what to use and didn't want to sand it. Piston contains square ring and very hard to find others. Bore looks/feels clean so don't think it's that.
Love the channel btw, very helpful, clear filming and down to earth. I'm in Chch, appreciate all you are doing in training a new generation of NZ mechanics 👍
@@AndyMechanic Thanks Andy. Further investigation reveals it's a blockage in the hole in the middle of the piston (very old disk brakes used a centering stem that went up the middle of the piston) that the stem can't get past.
Outer piston/bore was not the issue.
Ah...thanks for the extra info. I wasn't aware of the centre stem - not seen that design before, sorry.
Pleased you got it sorted :-)
Cheers Andy
Good demonstration. God I Hate binding brakes!
Hi, does anyone know if I should be able to push a new piston back in with my thumbs and push out any residual brake fluid and air?
what does it mean if ive replaced the seals and pistons, but the pistons are not retracting a visible amount? i cleaned under the seals like you said, polished up the chambers in the caliper and lubed up the pistons and seals with plenty of brake fluid, but they refuse to retract on their own. they arent difficult to push in by hand, there is little resistance but they arent moving in and out a visible amount like in the video.
Okay. Remove the pistons again & take the seals out. The pistons should then slide freely in each of their cylinders - if they are tight then either the pistons are deformed or the bore is - could be corrosion etc. Once you have them moving freely then refit the seals & test for piston retraction again.
Hope this helps
Andy
Andy Mechanic thanks for the speedy response! I just tested the pistons without the seals and they move freely without them, I cleaned the bores anyway but with the seals in it will not retract on its own with the compressed air and a cut line
Thank for the info, i have a weird application. Its a dirt track car only have one front drivers side brake caliper. It it locked up on the track and caught fire. Ive had the caliper rebuilt by a professional very reputable company.
Ive replaced the master cylinder , and brake line for goid measures. Ive even tried shaving down the pads.
When i instal the rotor spins free , soon as i pump the brakes it binds up.
Sent the caliper back to the company and it test perfect. It will not retract
When it binds on the vehicle loosen the bleed nipple on the caliper. If the piston(s) then retract & it stops binding you have residual pressure in the brake line - possibly poor adjustment of master cylinder push rod (no free play preventing piston in master cylinder from reaching the stop position against the circlip) or a faulty master cylinder or a blockage in the brake line itself - acting as a one way valve.
Cheers Andy
very good video
piston moves very slightly
Great vid. question On a 85 Goldwing front brake caliper, go to push in pistons to put new pads on and they wont go in, I can push 1 in at a time the other pushes out. so there not stuck. I opened the reservoir as well. So is it the seals ? can I just clean them or have to replace ? Thanks
Just upon the bleed nipple as you push each one in. Then do a couple of manual bleed pumps to ensure no air in the caliper :-)
Hi Andy..I have question for you.The problem is inside caliper housing the region between the groove for sealing ring and dust cover there is some scoring marks and surface is not smooth.what is the solution for this?
Assuming the pistons are not leaking brake fluid, remove the seals and and use 1200 grit or greater sandpaper 360 degrees round and round to smooth out the bores. I did it to remove discolouration and white corrosion-like deposits.
Hi Andy I’ve just watched your video on piston retraction.I’m trying to determine how easily the piston on the rear brake of my Honda CBR600 should move back into the caliper.I still have the brake line connected,with the caliper held in my hand,the piston moves out easily when I pump the brake,but it’s very hard to push back in,although when the caliper is on it’s bracket and over the disc with the pads in,the caliper,but with the pins removed,the pads do come off the disc,but I don’t think sufficiently,as the disc is warm to the touch after a run,any help would be appreciated thank you!
Hi Peter, sounds like there is corrosion build up behind the dust seal - this restricts piston retraction. You'll have to remove the piston(s) & the seals & clean behind them then reassemble.
Cheers Andy
So is it normal for new brake pads to drag a bit since there's not alot of retraction?
is there any mechanical disc brake caliper like we use in bicycle disc brake available because with hydrolic caliper your wheel is not free there is little resistance i am right,
If the Hydraulic caliper is working correctly and there is the correct amount of piston retraction then the disc should rotate freely.
Multumesc!🤝🤝🤝🤝
great information, much needed by me - quick query - don't you want to put maybe 3 brake pads in there to test the pistons retracting at the position they would be when installed on the rotor? surely that is where you would notice the issue if there is one since it would be closer to where the pistons are becoming corroded...
Thanks. It makes no difference as the pistons are the same diameter along their length.
Cheers Andy
about the best vid on yt
Thanks Martin :-)
That was very informative, thank you. I do have a question, how to clean pistons?
Hi, Thanks. To clean the pistons you can use a wire brush or very fine wet & dry sand paper - use a little oil with this option. It's important you don't score the surface, it must be smooth.
Hope this helps. Cheers Andy
Andy. Very informative and hands on! My question for you...albeit more than 7 years after posting the video...should you expect the same piston retraction if you carried out the same process with the caliper still attached to the hydraulics (that is, press the brake pedal to push the piston out, then release the pedal (and assuming there is nothing behind the dust seal, nor any crud behind the square cut seal to hinder the piston retraction)? Just trying to make certain that the calipers need servicing. I've already swapped out the flex hoses and still encounter brake drag on _both_ front wheels (rotor gets extremely hot (accompanied by a roaring noise (like tire sound on pavement) when driving, that fluctuates with speed). Any suggestions would be appreciated. Thanks!
Yes, you should clearly see piston retraction with caliper mounted on bike.
Cheers Andy
OK, trying to solve an issue on my 03 Trailblazer, I hit a chunk of semi tire on the highway with the passenger front wheel, somehow that chunk of tire smacked the edge of the caliper/caliper mounting bracket (there was visible damage, the caliper slide pin bolt actually grooved the hole the bolt goes through on the caliper) so I bought a new set of brake calipers, mounting brackets, rotors and pads. I installed the new fronts and bled them out, everything felt fine, I then a week or so later did the rear brakes (forgetting to open the bleeder screw when pressing the pistons back in) since this my front brakes have been running hotter, I decided to bleed the whole system to fresh fluid, that got the front passenger brake a little cooler but the driver front brake was still running hot, further testing revealed the lower piston of the dual piston caliper is not retracting and keeping the pad engaged, but the piston will compress fairly easily when compressing them so it's not frozen in the bore it's just not retracting like the upper piston is when the pedal is released, piston remains engaged even with the bleeder screw open so it's not the rubber brake hose (which was replaced less then 18 months ago). So everything points to an issue with the new caliper, well I swap back on the old caliper for that side (since I still had it and it wasn't damaged like the one on the other side was, note I had to buy them in pairs to get the ones I wanted, thats why I got the new driverside unit) and the same issue is happening with the old caliper, lower piston won't retract but will compress back in. This makes no sense to me, that was a properly working caliper when I removed it and why would only 1 piston on a dual piston caliper not retract on 2 different calipers?
This is very odd as the fluid has no effect on piston retraction, it's the square section main seal that provides this. I'd suggest popping the piston out, remove the main seal & clean - they may have used some rubber grease on assembly which is, in my opinion, bad as it changes the friction coefficient between the piston & the seal, reducing the distance the piston retracts.
Just out of interest, is there one or two brake pipes to the caliper?
Thanks
Andy
This is hapening to by front caliper lately. What to do to fix it?
andy, could you help,pergeo boxer van , 1/ failed MOT long travel on brake ped, when engin running, without engin running the pedel is hard and at the full hight, checked the servo ,ok , no leaks anywere, adjusted rear drums all ok. front disc have a twin cylinder piston, one large piston one smaller, the larger one is on the bottom of the calliper, 2/ without engin running pressing the brake pedel with the caliper hanging free, the brake peddal will not go to the floor, the small piston moves out and retracts, large piston only moves out , this is the best i can describe the problem, please help as i am loosing the plot.
many thanks from UK.
Evelyn Woodcock have you bleed the brakes?if so carefully pump out the pistons with the car off and caliper off its mounts and jam a pad or so inside caliper and little by little,check after each pump how far its come,then when its almost out and u can wiggle it,pinch off the brake hose with a set of vice grips and you are free to take out the pistons,carefull when u take ehm out much brakefluid will leak out, look for pittings and rust on the piston,also check integrity of main seal inside caliper,if either is kn bad shape buy a rebuild kit that fits your car. The brake often stay firm with the car off as the brake booster produce 10 times the brake power one person can do alone,then small leaks and air bubbles gets more noticable
Hy can y pull out the pistons clean everything and remount whitout change the seals?
Yes, no problem :-)
Great Video Andy. How do I remove really stuck pistons from my 1984 Honda Magna V65 motorcycle caliper?
Refit it back on the bike and bleed up. Then pump the brake lever and use the Hydraulic pressure to push the pistons out.
Cheers Andy
Per 1983 Honda v45 Intercepter factory manual I use grease gun full of atf or water on bleed nipple with correct m10 pitch bolt plugging banjo port. Pump pump pump.
should one caliper always go out before the other?
Cleaned and lubricated my caliper and pistons on my motorcycle, when i installed it back one piston went out to the brake pad and when it reached the pad the other one was coming out due to pressure. is this normal? bike is brand new 3000 km
Yes, that's fine. The piston with the least resistance will always move first.
Cheers Andy
But is it normal one piston will not move at all unless there's pressure on the other?
All pistons require some pressure to build in the hydraulic system before they start to move. This resistance cannot be exact the same on both pistons therefore the piston with slightly less resistance will always move first. If you stop it from moving the other piston should start to move.
Cheers Andy
my front caliper piston wont function at all, i bought 2 new ones and still nothing...although the other 3 works fine. could it be something wrong with my abs module causing the break caliper driver side not to respond ?
Yes, definitely. If the valve in the ABS module for that circuit has jammed in the 'hold pressure' position then no fluid pressure from the master cylinder will be passed to that caliper.
My first piston is ok but my second one won’t go back, how do I fix that?
I have so many questions ,aww I have a new remanufactured set pulled them apart and all the walls and and piston look well,but I'm still getting no retraction and the ring and dust boot look good new and good no cracks,but I am getting no retraction,how smooth do the pistons have to be to be about to retract and how tight do the seals have to be against the piston for smooth movement ?
Hmmm...normally the pistons can be pushed in by hand on motorcycle/ATV calipers. If the pistons are very tight then often it's due to corrosion build up in the grooves in the caliper body where the seals fit, excessive corrosion on the pistons or pistons that have been machined too large (which is rare).
Another reason for lack of piston retraction is the assembly grease they use. Remove the pistons & seals, clean them thoroughly to remove all of the grease then reassemble using only brake fluid as the lubricant then try again.
Cheers Andy
@@AndyMechanic I've done that now and rebuild the seal fits the bore nicely and the dust boot and clip fit nice as well,set it up as to test just like you did with compressed air and a block of wood in between but the piston still has no retraction ,the piston looks new and seems to all be correct with the bore but it seems like the piston isn't smooth enough or polished enough or some sort and its not retracting back and so once I place them on the car they continue to lock up,no pitting at all on piston or bore,piston doesn't seem to large ,seems to fit just right,but no retraction,could it be possible for the brake pistons to be re polished by a machinest or smoothed out some how ?
Why does my brake keep losing pressure in the handle after it's moved a foot or 2 and then I can pump it and it comes right back and it moves a little bit more and it goes away again after releasing the break and I have to pump it again what is going on
Likely too much piston retraction - may be caused by loose wheel bearings if it's got disk brakes
Need more info....
Ta
Andy
How about excessive piston retraction? I have a set of calipers I rebuilt and the left side retracts too far and I have a spongy brake handle. If I pump the handle long enough the piston will extend to the rotor giving a firm brake but as it retracts I have to re pump to get that piston back . I’ve bled the system with a power bleeder . Any advice would help, thank you
Yep. Remove piston & seals. Clean seals, clean groves where seals sit in casting, reassemble using only brake fluid, ensure piston outside diameter where seals run is clean & smooth. Should then be fixed. Cheers Andy
@@AndyMechanic thanks bud , I’ll give that a shot
It looks like my seals are slightly angled? If this is the case, what way do they face? Larger side facing hydraulic fluid? Thanks for the great video and tip. Will be taking my calipers off for a second time today, should have tested retraction before reinstalling and bleeding.. Oh well, lesson learned. Thanks.
Finished the job with success this time. Although I cleaned and polished the pistons yesterday, both seal recesses had white corrosion-like deposits in them. Used a pin and miniscule allen key to get in the recesses 360 degrees and scrape it all out. Piston bores were discoloured with the same kind of material so I gave it a caress with 1200 grit sandpaper. You mentioned very quickly a trick of using compressed air and a rag, which worked well for me to both eject the pistons and test retraction. Cheers Andy.
Have also come to the conclusion that because the seals are used, the hydraulic pressure may have made them appear to be angled in one direction. From what I gather from pictures, the seals do not appear to be angled and are square.
Is it normal when I don't have my foot on the pedal that my piston is still making the pads touch the rotors? It pops out but doesn't retract a whole lot. 2006 impala ss all OEM still... Time for new calipers?
Well, piston retraction is only a very small distance & does vary between different calipers too. Are your brakes binding? Does the disc spin freely or are the pads actually clamping against the disc (rotor) when the brakes are cold & pedal released?
Cheers Andy
The same methot on 4 piston caliper?
I hope you are still looking at these replies. You mentioned pushing on the brake pedal to move the caliper piston out. I've seen where some people said not to do that. In your opinion is it alright to push the brake to move the piston?
It's fine to do that, however, I'd suggest not pushing the brake pedal all the way to the floor as there may be some debris build up inside the master cylinder & this can cause it to enter the hydraulic lines. That, to me would be the only thing to be aware of. Cheers Andy
Exactly what im looking for , if the piston is hard to put in i had to use c clamp to put in i think the problem is the oring ,
Can i shave up the oring to make an easy entry?
You call it an o-ring but it's not. You can't change alter the seals. If they come into contact with other liquids other than the correct brake fluid they can react & expand. If this happens they must be replaced.
Hope this helps
Cheers Andy
@@AndyMechanic thanks very good video
i'm having problem with the caliper brake retraction, the piston can retract very well and when i release the brake handle there are a gap between the pad and the disk. However on the other side (the side that don't have pistons) the brake pad still in contact with the disk brake and when i rotate the wheel, it make a creechy high pitch sound wich is anoying and i believe it steal some energy from the wheel, make it less than perfect efficiency.
Okay. Check the slider pins. Your caliper floats and these two pins should move freely.
Hope this helps
Thanks Andy
@@AndyMechanic thank you for your replied, i forgot to say that my caliper and my pads are brand new, ran less than 100km at this point and everything is very clean, so i don't think it cause because of dirt, i don't know what cause this :(
Can you explain to me the float slider pins? or some relate key words should i google so i can look it up myself. I'm a noob and got alot yet to learn :)
Your vids are awsome btw
On my '85 ninja 600 my front pads slowly press on the discs til I come to a full stop and they won't release. Hopefully this is it.
Hi Bryan, do you mean that when you start riding the brake works okay (not binding) then the more time that passes (and applications of the brake) it starts to bind then just gets worse & worse until unrideable?
@@AndyMechanic Exactly! When they bind up in the front I can hold the same amount of throttle straight down the road but my front brakes eventually over power the rear wheel driving forward and stop the bike.
Calibre still continues to drag the wheel even after changing new Caliper any sort of solutions for this proplem.
Yes, release the bleed nipple, then to tighten it, this will check to see if there is any residual pressure in the hydraulic circuit. If the drag is less then you have a problem further upstream- likely master cylinder.
Also check caliper sliders if caliper only has pistons on one side.
Also check your wheel bearing, if it's got excessive play disc will not run parallel to caliper - this can also cause drag
Hope this helps
Andy
@@AndyMechanic i have changed changed caliper , master cylinder , sarbo and the weel bearing is all fine it's gets jammed time to time still trying to find the cause of it . Because of the drag i have to change clatch disk 3 times . Any way thanks for the help. 😋
Cool
Thanks for taking time to make such a great informative video. Have Brembo brand calipers on motorcycle, each caliper has for pistons and during operation of front brake lever only one piston comes out at a time resulting in uneven wear for that side set of brake pads. Do you have a link to another video you may have already made of how to inspect and remove the inner seals for each piston of the caliper? The Pistons in the calipers do not seem to be retracting and just as you pointed out in this video, there may be dirt and grime putting extra pressure on these seals. Thanks eh, stay healthy.
Yes, there is a couple of caliper rebuild videos, I think one is in the Yamaha RoV playlist
Cheers Andy
Thank you, going to view what's there...
nope, not quite what I need. What else can I try?
The pistons moving out individually & not together can only be due to more resistance on the 2nd piston - this will be caused by more dirt behind the seals, in the grooves of the piston body. You'll need to remove the calipers, strip out the pistons & seals & clean out where the seals sit.
Hope this helps
Andy
@@AndyMechanic I've already completely taken apart the calipers and removed all pistons and seals and cleaned everything out very well. Everything inside the caliper where the Pistons and seals are sitting is very smooth and clean
Do you have a video on rebuilding the caliper
Yes, just done one with Tool Girl Holley on a DR200 front caliper but there is a video covering the Viking one too... Cheers Andy
I have a Honda vtx 1800 and the front brakes sounds like bee's humming..Read other articles and other people said the same thing..The front tires spins freely..I have done everything except these seals Any comments would be appreciated..
Superb video. :)
What causes the Caliper piston goes out but not goes back in ?
Hi Stephen, piston is pushed out by hydraulic pressure. The ONLY reason why the piston retracts back once you release the brake is the square section main seal. This deal distortes as the piston is pushed out (inner face follows piston & outer face remains in groove in caliper body). The seal is made of rubber so has elastic properties & wants to return to its original shape (section) so to do this it pulls the piston back in.
If piston not retracting then it must be binding in some way - either badly corroded piston or it can be caused by dirt/corrosion build up in the grooves where the dust (outer) & main (inner) seals sit. This causes excessive clamping of the piston so it's much harder to move.
Hope this info is of help
Andy
is it possible to have too much retraction?
Definitely. I'm going to do a video on this in the next few weeks.
Great point to raise too.
Cheers Andy
can you do that same test while calliper is on the car?
Yes, totally :-)
pressing brakes slowly? any tips
Yes, with the caliper lifted away from the brake pads to you can see the piston. Only really works on single piston calipers when on car otherwise it gets a bit difficult.
Thank you Great idea !!!!
Oh and will that lower fluid in my Master?
They go back in that easy when they aren't on the vehicle correct? They shouldn't be that easy on the car right? I use a c clamp to retract them. Have I been doing it wrong all along?
Hey Cody, car ones are a little harder to retract but using a g-clamp it should not require much turning force. So long as you get a small amount of retraction when you release the brake pedal - disc rotates freely & no binding then it's fine :-)
Cheers Andy
@@AndyMechanic Thanks for the reply Andy 👍