brake fluid

Post by **Pascal** » Fri Sep 28, 2007 10:39 am

Sorry for the mondane question by just got a call from my wife saying moggy has no brakes anymore! Can it be just down to brake fluid level, which I haven't checked since last service 2000 miles ago? I did check the shoes at the time and there were plenty.

I drove the car two days ago and found that it would still brake but there was quite a lot of travel of the pedal before it did (pedal down to the floor).

I'm going to get some brake fluid on my way home tonight just in case. Is it just normal DOT4 brake fluid?

Regards

Post by **Orkney** » Fri Sep 28, 2007 10:44 am

Far as i know just use the normal dot 4 if you cant remember what was in there before - think you have to avoid the silicone one as that can knacker the rubber parts over time.
If your losing fluid you shouldnt be - could be the master cylinder workings playing up? Or if you do have a leak it might be one of the actual cylinders in the drums. You should be able to spot that by whipping the wheels and drums off - any leak that bad would be pretty obvious.

Post by **bmcecosse** » Fri Sep 28, 2007 10:58 am

Dot 3 or 4 is fine. But you must have a leak!! So you will need to find abd rectify it.

Post by **Pascal** » Sat Sep 29, 2007 5:23 pm

The master cylinder was indeed completely empty - not good. Refilled it and brakes are back. I've checked the wheel cylinders and indeed one leaks on the nearside front wheel.

It looks reasonably straightforward to swap & bleed it. Anything to watch when doing it?

Regards

Post by **bmcecosse** » Sat Sep 29, 2007 5:58 pm

Well - it is easy enough although one of the fixing screws is very small and sometimes difficult to get out. Much easier will be to stick new seals in the cylinder which you can do without removing the cylinder. This may or may-not work depending on the state of the cylinder but I would say 4 times out of 5 it will be fine. If fluid has spread onto the brake linings you need new ones - no way round this - they must be renewed.

Post by **RogerRust** » Sat Sep 29, 2007 6:33 pm

In my youth I used to boil contaminated shoes in Daz for 20 minutes
But I agree its best to replace contaminated ones.

Post by **jtd.75** » Sat Sep 29, 2007 7:35 pm

I bet they made a noise when you put them in the tumble drier

Post by **bmcecosse** » Sat Sep 29, 2007 9:17 pm

Oh I've boiled up a few brake shoes myself - and roasted them with a blow lamp - but it doesn't really work!

Post by **Pascal** » Sun Sep 30, 2007 8:30 pm

By the way when I pumped with the brake pedal I saw that the fluid that was coming back was quite murky. I probably need to renew the fluid completely. What is the best way of doing that? Should I just bleed while topping up until clean fluid comes out at each wheel?

Regards

Post by **bmcecosse** » Sun Sep 30, 2007 8:36 pm

Yes -that's the idea. Should really be done annually to keep moisture content down - which helps prevent internal corrosion on the cylinders.

Post by **MoggyTech** » Sun Sep 30, 2007 8:42 pm

Pascal wrote:By the way when I pumped with the brake pedal I saw that the fluid that was coming back was quite murky. I probably need to renew the fluid completely. What is the best way of doing that? Should I just bleed while topping up until clean fluid comes out at each wheel?

Regards

Purging the entire system is fairly easy, but make sure you purge the master cylinder by bleeding one brake line only. Let the level drop as low as possible before topping up to minimise contamination of the fresh fluid. Then bleed the remaining lines to get fresh fluid into the whole system.
Every two years is adequate.

Post by **Pascal** » Sun Sep 30, 2007 8:52 pm

Thanks. How much brake fluid do I need for a complete purge?

Regards

Post by **MoggyTech** » Sun Sep 30, 2007 9:03 pm

Pascal wrote:Thanks. How much brake fluid do I need for a complete purge?

Regards

I have disc brakes with a remote fluid tank so need more than standard Moggy, but a Litre does the entire job. Always use fresh fluid from sealed container. You can buy two half litre bottles and save the second bottle for any top ups, a bit dearer due to packaging but handy.