Shimano brakes piston leak

[PerthMTB]

Yep. Fairly standard split caliper hydraulic system. CBC or a brake company will be able to match the square seals if needed.

It'd be great to get spare piston seals and O rings, as they are really the only wear items in the whole caliper, and would basically mean they could last for ever! But I'm dubious that motorbike/automotive applications would use piston seals so small, but I'd love to be proved wrong! If anyone finds the specs and a supplier please post here...

 

[teK--]

Great info thanks for the post PertMTB!

 

[moorey]

Tek, I have a caliper that has a cracked piston. O rings were fine. Yours if you want to try to remove bad use the O rings.

 

[cobba]

It'd be great to get spare piston seals and O rings, as they are really the only wear items in the whole caliper, and would basically mean they could last for ever! But I'm dubious that motorbike/automotive applications would use piston seals so small, but I'd love to be proved wrong! If anyone finds the specs and a supplier please post here...

A business like the following is where you'd get what you want.

http://hytechseals.com.au/index.html

I know of someone on another forum that got some piston seals from that business for $3 a piece, he bought 3 sets for a pair of 4 piston brakes (24 seals), I don't know if there was a minimum amount that he needed to get made.

The person who bought them had a TRP Parabox brake and he wanted attach some more powerful 4 piston calipers that used mineral oil, he worked out that the piston sizes of the Shimano Saint/Zee were too big to work with the TRP master cylinder but he found the Avid XO Trail had piston sizes that would work with the TRP master cylinder.
To attach the Avid's he needed to convert them to use mineral oil but he couldn't find anywhere that had seals that would work, he was looking for suggestions so I told him to contact that business to see if they could make what he wanted, they said that they could and he got some made.

I'd say that to get them made he would of needed to give them a bit of info about the seal size, the seal shape, the piston/bore diameter, the material they need to be made from, ect.

He also needed some mineral oil compatible o-rings for the brakes too, I think that he got them from the business below.

http://www.conbear.com/files/content.php?sec=products&sec2=lubrication-and-other-products&sec3=o-rings

He needed 3 different size o-rings, that business would only sell them in bags of 25 for each size, a bag of 25 o-rings cost him from $2.60 to $2.80

The Avid XO Trail was successfully converted to use mineral oil and the owner sounded like he was happy with the performance of his new brakes.

 

[teK--]

Tek, I have a caliper that has a cracked piston. O rings were fine. Yours if you want to try to remove bad use the O rings.

Thanks mate already got a caliper on its way though. 1 credit to you for redemption in future

 

[teK--]

A business like the following is where you'd get what you want.

http://hytechseals.com.au/index.html

I know of someone on another forum that got some piston seals from that business for $3 a piece, he bought 3 sets for a pair of 4 piston brakes (24 seals), I don't know if there was a minimum amount that he needed to get made.

The person who bought them had a TRP Parabox brake and he wanted attach some more powerful 4 piston calipers that used mineral oil, he worked out that the piston sizes of the Shimano Saint/Zee were too big to work with the TRP master cylinder but he found the Avid XO Trail had piston sizes that would work with the TRP master cylinder.
To attach the Avid's he needed to convert them to use mineral oil but he couldn't find anywhere that had seals that would work, he was looking for suggestions so I told him to contact that business to see if they could make what he wanted, they said that they could and he got some made.

I'd say that to get them made he would of needed to give them a bit of info about the seal size, the seal shape, the piston/bore diameter, the material they need to be made from, ect.

He also needed some mineral oil compatible o-rings for the brakes too, I think that he got them from the business below.

http://www.conbear.com/files/content.php?sec=products&sec2=lubrication-and-other-products&sec3=o-rings

He needed 3 different size o-rings, that business would only sell them in bags of 25 for each size, a bag of 25 o-rings cost him from $2.60 to $2.80

The Avid XO Trail was successfully converted to use mineral oil and the owner sounded like he was happy with the performance of his new brakes.

Great resource I reckon pull dud caliper apart and send them a seal to copy. Get a few dozen made for whoever else wants them.

 

[teK--]

Installed new caliper, the o-rings on the banjo were still in good nick so I reused them. Torquing the banjo correctly last time might have helped (8-10Nm). I did buy a BH90 hose kit just in case though, so that'll go into the spare parts bin.

$50 and I was back on the trails, bonza!

The piston seal was absolutely shagged by the time I got to this. It explains why I had a recurring brake squeal issue for the last 3 months which I only postponed by cleaning the pads and rotors after each ride :whistle: