bleeding bleeding brakes!

[rob wilsher]

I recently arrived home aware that the brakes were feeling rather light and when I checked the fluid reservoir it was virtually empty!

Anyway as I was going on holiday the following day I locked her up in the garage for another day.

 

Today has been that day and I am totally confused.

 

1) I checked each wheel and found no signs of fluid so:

 

2) I removed the master cylinder and stripped it to find a couple of jellified rubber seals so:

 

3) I hopped over the Severn Bridge to Moss at Bristol and returned with a repair kit which:

 

4) I carefully used in reassembling the master cylinder.

 

5) I reinstalled master cylinder in car and topped up with new DOT 5 silicon fluid

 

6) With my daughter's help I bled the system from back to front using the tube in fluid method-got rid of loads of air and tightened the nipples when the pedals were down.

 

RESULT---Pedal goed straight to the floor NO BRAKES!!!!!!

 

Something I am puzzled about is: should I put fluid into the front section of the reservoir? if not what is this section for? I can't find any mention of it in the workshop manual that I have been using.

 

I still don't know where the fluid has been going.Any ideas ??????

 

Rob

[Jersey Royal]

Something I am puzzled about is: should I put fluid into the front section of the reservoir? if not what is this section for? I can't find any mention of it in the workshop manual that I have been using.

 

 

 

Rob

Hi Rob,

 

I always thought that the two sections were for back and front, and when i did a recent brake overhaul i filled both chambers.

 

Hope this helps.

 

Regads

 

Guy

[mikew]

Vanishing brake fluid can often end up inside the servo, and sometimes from there to the inlet manifold - where it vanishes as traces of white smoke from the exhaust.

 

did you check for scoring in the cylinder bore ?

 

and yes the front section of the reservior should have fluid in it.

 

from a safety aspect I would simply get a new master cylinder, I know its more money, but you should be able to assume the seals are correct, correct diameter, and correctly assembled.

 

mike

[rob wilsher]

and yes the front section of the reservior should have fluid in it.

 

 

 

 

There seems to be hardly any clearance to top up this section which I assume is for the rear brakes-that's why I was unsure.

 

Cheers Rob

[jean]

Yes Rob, this resevoir is one of my favourites in the most stupid designs I have seen. Depending on the car's position the reservoir will float over before the front part is accepting fluid On my 6 I did cut an about 7mm deep V in the partition, so the front part is filling without spill

Considering the actual price it's, as mentioned, adviseable to replace the master cylinder completely. Anyhow the steel quality of the cylinders is now so bad that they show rust traces within a few years.

It seems that TR Shop is selling a master cyl/servo package at a very reasonable price, a few years ago you paid more for the master cyl. alone

[Andy Moltu]

The front section is the reservoir for the rear brakes. You will need to refill this & bleed the rears too before you will get a firm pedal.

The brake seals should only be replaced if you are certain the bore is unmarked & perfectly smooth or the new seals won't last long with potentially catastrophic consequences.

[Richard Crawley]

Although common practice some years ago, I now believe it’s a false economy to re-rubber brake cylinders, especially the master! They are relatively inexpensive & for safety’s sake I would advise you replace with new. If you can’t find any trace of a fluid leak, it’s almost certain it's gone into the servo as suggested, this probably hasn’t done the servo diaphragm much good either so I would advise you replace that as well, if you can get it apart! While you’re at it, you might as well replace the rear cylinders & overhaul the front callipers; you’ll probably be amazed at how good the standard 6 brakes are after that lot!

[jean]

Fully agree Richard, although they still functioned perfectly, I have overhauled the brakes on my 6 after 10 years of using Silicon fluid and found a deposit of water and rust in the lowest part of the calipers, as silicon and water don't mix, the damp will collect at the bottom of the calipers and stay there. To get it out, the only solution would be to lock the pistons and turn the calipers upside down when bleeding the system

The jelly seals are probably the result of replacing Dot3/4 by Dot5 without changing the seals, have seen this several times, the seals slowly start to disintegrate.