SRAM Guide RS Brakes - Lever slow to return
- Thread starter Jesterarts
- Start date
bowtajzane
Likes Dirt
good job bro....
are the black marks on the right from the piston
scraping/ getting stuck ?
are the black marks on the right from the piston
scraping/ getting stuck ?
Jesterarts
Likes Dirt
Looks like the new piston has a lot more clearances at each point.
The widest OD is now 9.35Mk on it... So 0.075mm gap between the piston and the bore all round.
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Jesterarts
Likes Dirt
Just finished my rebuild. Old pistons looked the same as your's link. That fat bit had the most scarring on it from rubbing on things.
Now I just need to bleed them once the brake fluid arrives.
Now I just need to bleed them once the brake fluid arrives.
Nambra
Definitely should have gone to specsavers
You'd have to think that scarring would be normal, as that part of the piston is outside the seals and prone to all the dirt entering through the bore from the outside.
Jesterarts
Likes Dirt
Agree. It actually strikes we as a bit of a design flaw to allow the piston to be that unprotected. I would think that there should be a rubber boot or something given its a spot were debris and dirt can get into, but there is no easy way to clean it. Below are some terrible pictures I tried to take on my phone.
Key things I noticed:
1. So much crap on the lever
2. There was a LOT of crap behind the outer seal. It was obviously doing it's job to keep it out from going any further but given how much build up there was, I suspect this would contribute to the sticking issue.
3. The main scarring was on the bit fat bit, with only very minor scarring on the bits past the outer seal
4. That C-clip is a c##t to get out and a c##t to get in. My pliers where about 3mm too short to do it easily
Attachments
bowtajzane
Likes Dirt
i hope you put a patent on your one.....
i can't believe how much crap gets inside,no wonder they shit themselves
i can't believe how much crap gets inside,no wonder they shit themselves
bowtajzane
Likes Dirt
link, how did you go with the new piston and have you got a link to the shaft seal,tried a search but came up blank
link1896
Mr Greenfield
New piston is nice, but haven't swapped the new rebuilt lever onto the bike yet.
By shaft seal, are you talking about the OEM rubber seals on the piston?
Jesterarts
Likes Dirt
I think he means the shaft seal in the picture you posted of the HOPE piston kit.
link1896
Mr Greenfield
I did too but was seeking clarification the hard way.
Have a few ideas how to make something similar to HOPE's pushrod rubber seal for guides.
bowtajzane
Likes Dirt
yep,sorry dude, was talking about the hope ones.....
but if you have a alternate plan I'm all ears...
but if you have a alternate plan I'm all ears...
Jesterarts
Likes Dirt
I just had a brilliant idea!
Just cut them down to length... Just have to push the piston pushed thing through it.
Just cut them down to length... Just have to push the piston pushed thing through it.
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Jesterarts
Likes Dirt
Looking good!
merc-blue
Likes Bikes and Dirt
Side note have any of you contacted your LBS about this issue? seems to be alot of effort going into a problem that is fixed with WAY less effort,
I always find it funny when people put heaps of work into fixing something before contacting someone who may fix it, just had a pair of levers replaced FOC by Sram, they were replaced with a revised/updated lever.
when I used to do alot of work for a specialist area of the industry it used to amuse me the amount of effort and stress put into problems that would just go away if you called a decent shop.
I always find it funny when people put heaps of work into fixing something before contacting someone who may fix it, just had a pair of levers replaced FOC by Sram, they were replaced with a revised/updated lever.
when I used to do alot of work for a specialist area of the industry it used to amuse me the amount of effort and stress put into problems that would just go away if you called a decent shop.