Brake master cylinder piston slow to return

[Jersey Royal]

Hi All,

 

After a pleasant blat round the Island i decided to fit the anti squeal shims that came with my Mintex pads.

 

Whilst i was at it i thought i would give the front brakes a quick bleed.

 

Pressed the pedal down, fine, let it up pushed it again and there was no resitance as if the piston wasnt there

let it up then pushed again fine. So seems to me that my piston in the MC is slow to return I have read that

some Mc on other vehicles are slow to return.

 

Mc has recently had new seals due to a change from silicon to dot 4. The Mc is one of those that came from

Tr shop .

 

Can anyone shed any light on this?

 

Your thoughts appreciated

 

Cheers

Guy

 

Edit,

I was doing the bleeding unaided with one man bleeder, could this be the reason for the piston not returning, ie the nipple is open? Brakes seem fine otherwise.

Edited March 24, 2012 by Jersey Royal

[Rien]

Hi, I have this had many times on other cars with the clutch and brake master cyl. before, It comes by swollen seals, broken return spring(s) or oxidated piston and or liner.

 

Good luck,

Rien

[Grabea]

I've come across this with other cars when bleeding brakes this way, as you're using a part of the cylinder where the piston doesn't normally reach this can cause these problems which is why I always use the Gunson pressure bleeder. Hopefully you'll get away with a strip and clean of the M/C.

Good luck

Graham

[Rien]

Hi Graham,

Yes your right the pressure bleeder are a Indeed a handy tool, but the Piston spring(s) themselves should be able to push back the piston and to suck the liquid to!

 

Rien

[Guest ntc]

Guy

 

You have mail

[Jersey Royal]

Thank you Rien, Graham and Neil.

Most helpful.

 

I am going to take the MC off, and check it all through. Most probably tomorrow.

 

Then put it in a vice and do a bench bleed, then i can see what is going on.

 

Sound s like a plan.

 

Cheers

GUY