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Do you clean & lube your brake pistons?

ragnor

Active member
Apr 23, 2020
144
286
U.K.
So do you clean & lube your disk brake pistons? If you don’t then why not? If you do what gear, greases, lubes etc do you use?
 

militantmandy

Well-known member
Jan 18, 2022
399
369
Tweed Valley, Scotland
When I had Code RSC I did this regularly as it was the only way to keep them feeling nice. Not something I have done often with other brakes unless they are disgusting. With the Codes, I used a little 3d printed template my friend lent me. It allows you to expend 1 piston out at a time without it coming totally out. Then I would clean with IPA (not Brewdog!) and lube with the SRAM brake fluid. Tedious, but it did help. RSCs in perfect health are superb, they just seem to take a lot of faff to keep them feeling nice.
 

2WheelsNot4

E*POWAH Master
Oct 17, 2021
918
712
Scotland
Hunter's silicon lube on the piston sides. Nothing finer.
s-l1600.jpg
 

p3eps

E*POWAH Elite World Champion
Subscriber
Dec 14, 2019
1,982
2,398
Scotland
I was shortening my front brake hose last night after getting some more olives / barbs.

Whilst doing this, I had the caliper off, and gave it a good clean out with Wurth brake cleaner, and using my new brushes that I bought from Amazon for pennies!

I then folded up a rag, and ran it back and forth through the caliper.

I've never considered lubricating the calipers, as I always assumed they'd be self lubricating with the brake fluid that's pushing them out each time I pull the lever?
 

militantmandy

Well-known member
Jan 18, 2022
399
369
Tweed Valley, Scotland
I was shortening my front brake hose last night after getting some more olives / barbs.

Whilst doing this, I had the caliper off, and gave it a good clean out with Wurth brake cleaner, and using my new brushes that I bought from Amazon for pennies!

I then folded up a rag, and ran it back and forth through the caliper.

I've never considered lubricating the calipers, as I always assumed they'd be self lubricating with the brake fluid that's pushing them out each time I pull the lever?
That's definitely how they're supposed to work, but some seem a bit better at it than others.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,567
5,058
Weymouth
Yes....but mostly the rear brake since the front brake orientation behind the fork lower means it is better protected from mud and dust.
I use a calliper block that allows only one piston at a time to be extended and clean the piston with IPA and a cotton wool bud. Then lubricate with dot 5. Once all pistons are cleaned and lubed and pushed back, I clean the calliper with IPA.
All my brakes are Code RSC.
 

Dax

E*POWAH Elite World Champion
May 25, 2018
1,726
2,112
FoD
Yes....but mostly the rear brake since the front brake orientation behind the fork lower means it is better protected from mud and dust.
I use a calliper block that allows only one piston at a time to be extended and clean the piston with IPA and a cotton wool bud. Then lubricate with dot 5. Once all pistons are cleaned and lubed and pushed back, I clean the calliper with IPA.
All my brakes are Code RSC.

How often do you do that?
 

Tubby G

❤️‍🔥 Hot Stuff ❤️‍🔥
Dec 15, 2020
2,696
5,421
North Yorkshire
Yes. Occasionally. Remove pads, extend pistons, spray with brake cleaner, run a thin cloth through calliper to dry off. Extend one piston at a time and use cotton wool bud dipped in mineral oil specific to brake and lubricate sides of calliper with a tiny amount. Push piston back, do the next one and so on. I only usually do it though if the brakes don’t feel spot on, and following a minor bleed (not a full bleed, the cheat bleed).
 

Mcharza

E*POWAH BOSS
Aug 10, 2018
2,617
5,393
Helsinki, Finland
When I had Code RSC I did this regularly as it was the only way to keep them feeling nice. Not something I have done often with other brakes unless they are disgusting. With the Codes, I used a little 3d printed template my friend lent me. It allows you to expend 1 piston out at a time without it coming totally out. Then I would clean with IPA (not Brewdog!) and lube with the SRAM brake fluid. Tedious, but it did help. RSCs in perfect health are superb, they just seem to take a lot of faff to keep them feeling nice.
I totally agree this. I was so tired to clean pistons almost every week or even day at Alps this year and changed the brake to Shimano XT and sold the Code RSC.
No more piston problems, no more DOT poison.
 

RustyIron

E*POWAH Elite World Champion
Subscriber
Jun 5, 2021
1,838
2,870
La Habra, California
Just like so many others, I do it when I change pads or bleed the brakes. I clean with alcohol and then finish with mineral oil brake fluid. The difference is that we Yanks don't use "cotton wool buds." We like "Q-Tips."

When working on brakes that use glycol/ether brake fluid, I finish with a thin film of McKay Brake Cylinder Assembly Lube. It's specifically made for just this sort of application.
 

Alexbn921

Well-known member
Sep 27, 2021
545
511
East Bay CA
You should always clean the pistons with 99% alcohol before pushing them back in. You don't want all that crap getting into the seals.

NEVER use anything to lube the outside of the pistons as it will only attract dirt and make things worst.

To "lube" the pistons you cycle them in and out sever times until they move freely. This pulls a super thin layer of brake fluid into the square seals and keeps them from drying out. The pistons that move easy should be held compressed and the sticky ones cycled until they are all moving the same.
 

ragnor

Active member
Apr 23, 2020
144
286
U.K.
Many thanks for the replies. Being a bit of a hamfisted & clumsy old git it's always useful to get information from people who have actually carried out the work. Theory & YouTube is fine but hands on info is best
 

RustyIron

E*POWAH Elite World Champion
Subscriber
Jun 5, 2021
1,838
2,870
La Habra, California
No, not as routine maintenance. They don't need maintaining. Do you maintain them on you car?

As a matter of fact, I DO maintain them on my vehicles. With every brake job, the caliper gets disassembled, cleaned, and new seals. Anything less seems... average. Maintain things in an average way, and get average performance.
 
  • Haha
Reactions: Dax

Gman086

Member
May 11, 2021
32
23
Portland, OR
I clean when I change the pads, I use soapy water and a toothbrush
Over time the seals go hard and the pistons stick, the only solution is to replace the seals.
^^THIS!

I can tell you there is a LOT of sketchy info in this thread... I've wrenched bikes for over 30 years and here is my take:
Most brakes are fine with doing just what Goff does. Sram brakes are prone to the sticking piston issue, near as I can tell, because of seal/piston tolerances. Their phenolic pistons in their RSC versions are just as bad so we know it's not due to piston expansion. At some point I'm sure they will get it resolved but it has been an issue for a while now.
Whoever came up with the "use the same fluid on your pistons as a lubricant" thing is... I'll just use the word "misinformed" as all that will do is attract dirt and wear your seals faster. I don't use any lube except for with problematic Srams and then I will only use silicone like the Permatex red. 2WheelsNot4 got that one right because it won't degrade the seal material. Do NOT use isopropyl alcohol (IPA) to clean the pistons with the seals in place because it degrades seals (ESPECIALLY the 99% version). If you can't get the pistons clean with soapy water then you've likely got seal degradation onto the pistons and your best bet is to remove the pistons, NOW clean with IPA, replace the seals and re-bleed.

Have FUN!

G MAN
 

Alexbn921

Well-known member
Sep 27, 2021
545
511
East Bay CA
^^THIS!

I can tell you there is a LOT of sketchy info in this thread... I've wrenched bikes for over 30 years and here is my take:
Most brakes are fine with doing just what Goff does. Sram brakes are prone to the sticking piston issue, near as I can tell, because of seal/piston tolerances. Their phenolic pistons in their RSC versions are just as bad so we know it's not due to piston expansion. At some point I'm sure they will get it resolved but it has been an issue for a while now.
Whoever came up with the "use the same fluid on your pistons as a lubricant" thing is... I'll just use the word "misinformed" as all that will do is attract dirt and wear your seals faster. I don't use any lube except for with problematic Srams and then I will only use silicone like the Permatex red. 2WheelsNot4 got that one right because it won't degrade the seal material. Do NOT use isopropyl alcohol (IPA) to clean the pistons with the seals in place because it degrades seals (ESPECIALLY the 99% version). If you can't get the pistons clean with soapy water then you've likely got seal degradation onto the pistons and your best bet is to remove the pistons, NOW clean with IPA, replace the seals and re-bleed.

Have FUN!

G MAN
You can't replace the seals on Shimano brakes. They don't sell them. :(
 

militantmandy

Well-known member
Jan 18, 2022
399
369
Tweed Valley, Scotland
^^THIS!

I can tell you there is a LOT of sketchy info in this thread... I've wrenched bikes for over 30 years and here is my take:
Most brakes are fine with doing just what Goff does. Sram brakes are prone to the sticking piston issue, near as I can tell, because of seal/piston tolerances. Their phenolic pistons in their RSC versions are just as bad so we know it's not due to piston expansion. At some point I'm sure they will get it resolved but it has been an issue for a while now.
Whoever came up with the "use the same fluid on your pistons as a lubricant" thing is... I'll just use the word "misinformed" as all that will do is attract dirt and wear your seals faster. I don't use any lube except for with problematic Srams and then I will only use silicone like the Permatex red. 2WheelsNot4 got that one right because it won't degrade the seal material. Do NOT use isopropyl alcohol (IPA) to clean the pistons with the seals in place because it degrades seals (ESPECIALLY the 99% version). If you can't get the pistons clean with soapy water then you've likely got seal degradation onto the pistons and your best bet is to remove the pistons, NOW clean with IPA, replace the seals and re-bleed.

Have FUN!

G MAN
So what would you clean with after a bleed? Will soapy water be enough?
 

iamanej

Member
Apr 3, 2023
58
24
Slovenija
So do you clean & lube your disk brake pistons? If you don’t then why not? If you do what gear, greases, lubes etc do you use?
I spray them with brake cleaner, then I put some brake oil on cotton ear pads and lube them.
Afterwards I push them back in, insert the brake inserts (the ones you use for bleeding), push the lever to push out the pistons and repeat the process for a few times (until the pistons come out evenly).
 

iamanej

Member
Apr 3, 2023
58
24
Slovenija
When I had Code RSC I did this regularly as it was the only way to keep them feeling nice. Not something I have done often with other brakes unless they are disgusting. With the Codes, I used a little 3d printed template my friend lent me. It allows you to expend 1 piston out at a time without it coming totally out. Then I would clean with IPA (not Brewdog!) and lube with the SRAM brake fluid. Tedious, but it did help. RSCs in perfect health are superb, they just seem to take a lot of faff to keep them feeling nice.
would you be so kind to share this 3d model?
 

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