Brake master cylinder operation?

[AndyP]

My master cylinder seems to have failed as I'm not getting any fluid through to the rear brakes. I've got hold of a used one, but it appears to have the same fault as mine, I just want to check that I'm understanding it's operation correctly.

Here is the cyclinder stripped and on the bench.


When I pump the piston, only the left hand bore ( front brakes? ) is taking any fluid, the right hand one does nothing. This is not right is it?

I'm going to strip if fully as soon as I work out how to get this out

[Error404]

I think there are twin pistons inside, sequential on the pushrod - maybe one of the seals has rolled?

You need to drill holes in that blank circlip, I have tried to do that but didn't get anywhere with domestic tools
Or you could notch that sides of the housing to get at the clip.

[AndyP]

You're right about that circlip, it's a bitch to drill!

[jade]

My master cylinder seems to have failed as I'm not getting any fluid through to the rear brakes. I've got hold of a used one, but it appears to have the same fault as mine, I just want to check that I'm understanding it's operation correctly.

Here is the cyclinder stripped and on the bench.


When I pump the piston, only the left hand bore ( front brakes? ) is taking any fluid, the right hand one does nothing. This is not right is it?

I'm going to strip if fully as soon as I work out how to get this out

Is it connected to anything ? try connecting it to a slave to test it

[AndyP]

Got a brand new master cylinder today. GSF and ECP were both useless, claiming they couldn't get one despite me providing all the part numbers

Ended up going to the local brake specialist and they had one on the shelf. Cost was £95, expensive but not bad compared to some of the prices I'd seen quoted dealers on here. Make is LPR, not heard of them before but I goggled them and they seem like a reputable brand from Italy, certanly no Chinese back street sweat shop

There is also some useful info on various manufacturers part numbers on their website so you can cross reference.

http://www.lpr.it/e-idraulicascheda.asp?LPR=1384

I'll report back when it's fitted and working, I'll also continue my quest to strip the old one and I'll post up pics when it's in bits.

[DeS]

Andy, can you give some feedback about this LPR brake master cylinder?

[Pirvu Eugen]

Hy! You can create a small cut in the circlip edge as in the picture and than, using some screwdrivers you will be able to take out the clip.
Is not the best cut in the picture but give you an ideea!
All the best!

[Pirvu Eugen]

BTW! The rear cylinder will push liquid either iff the fronts are pressurized and the actual fronts pressure is pushing the rears piston...or iff you press the master shaft all the way in...
Makes sense?
Regards!
Eugen

[AndyP]

Andy, can you give some feedback about this LPR brake master cylinder?

Still working fine

[Pirvu Eugen]

Lol!! Now i saw how old this thread is!!!
I have to spend some more time here.

[newsh]

Only 4 years I just bumped an older one

[andy10v]

I'm going to strip if fully as soon as I work out how to get this out

A bit late in this instance but I have removed that style of circlip at work by drilling the housing.

Measure the depth to the cirlip, venier depth guage is perfect, but marking wire etc works
Mark the position on the outside
2.5mm drill bit, drill through the alloy until you hit steel
Push the cirlip out its groove with an old drill bit, seal pick etc
Use a 90* seal pick/small flat screwdriver to pull the clip up and out

A drop of glue, jb weld etc will keep dirt out if needed

Lets you service a few things that the manufactures only sells complete.