brake Q

Post by **Peetee** » Wed Feb 07, 2007 11:36 pm

I have fittedfront disc brakes to Joemog. The master cylinder valve was removed as per instruction but what need to know is if it is vital that this is replaced if I ever convert back to drums?

Post by **bigginger** » Thu Feb 08, 2007 12:26 am

Yeah, I'd say. It's there for a reason.

Post by **rayofleamington** » Thu Feb 08, 2007 1:14 am

It depends what you mean by vital - it is extremely useful, but I've had 2 drum braked minors where it was not functional (one had been like that since new).
Without the valve, you can't pump up nearly as well. Therfore the system is FAR less tolerant of air or lack of wear adjustment.

Think of it like a seatbelt - normally not needed therefore normally pointless, but extremely useful if it is needed!

Post by **moggyminor16** » Thu Feb 08, 2007 5:20 pm

do you need to take the valve ou when fitting disk brakes as if not hurting then why worrie as i am thinking of fitting disk to my traveller

Post by **bigginger** » Thu Feb 08, 2007 5:22 pm

If you don't, the pads will be permanently rubbing against the discs, if my understanding's right

Post by **jonathon** » Thu Feb 08, 2007 5:24 pm

Correct BG

Post by **Willie** » Thu Feb 08, 2007 5:25 pm

Yes, you do need to remove the valve for disc brake operation. Disc brakes rely solely on the pull of the piston seals to pull the pads away from the disc after the brakes have been operated so you do not want the residual pressure supplied by the Master Cylinder valve because it causes the pads to rub all the time.

Post by **moggyminor16** » Thu Feb 08, 2007 5:31 pm

right in this case what dose the valve look like sorry for getting simple but i have never takern a master cylender apart yet

Post by **rayofleamington** » Thu Feb 08, 2007 6:00 pm

right in this case what dose the valve look like sorry for getting simple but i have never takern a master cylender apart yet

it's a little rubber cup - it fits inside a little steel top hat at the bottom of the m/c bore.

Post by **Peetee** » Thu Feb 08, 2007 11:59 pm

It depends what you mean by vital

Given that we are talking brakes I'd say would the absence of the valve compromise their safe operation in any way?
Basically I'm being lazy. Joe is to be sold soon minus his 1275 engine and disc brakes. I'm going to struggle to find the time to do this work as it is and I don't want to spend hours removing the MC if it deosn't really need doing.

Post by **bmcecosse** » Fri Feb 09, 2007 7:42 am

I would try it - and see what happens. If the brakes are found to be dragging - then you will need to do the modification. If not - then it will be fine. Don't expect the wheel when jacked up to spin freely - that doesn't happen on modern cars either - they rely on the small disc run-out to push the pads ever so slightly back from the discs - there is always some drag. It is unfortunately one of the snags of fitting disc brakes to these cars.

Post by **Willie** » Fri Feb 09, 2007 9:06 am

Peetee, to answer your original question then yes, you should replace the valve if reverting to drum brakes or at least inform whoever buys
the car because there is obviously likely to be more pedal movement without it.

Post by **rayofleamington** » Fri Feb 09, 2007 8:37 pm

You can just remove the little rubber cup - then after selling the car, give it to the new owner with an explanation of what it is for and let them decide what to do with it ;-)

Post by **bmcecosse** » Sat Feb 10, 2007 9:21 pm

New owner will be well pleased with that!

Post by **les** » Sat Feb 10, 2007 9:48 pm

Can imagine the sales pitch, 'Yes she's a good little runner----- Oh by the way this thing belongs in the braking system, do you want it!'

Post by **Kevin** » Sun Feb 11, 2007 10:00 am

Can imagine the sales pitch, 'Yes she's a good little runner----- Oh by the way this thing belongs in the braking system, do you want it!'