Brake Problem

Hi

I took my bertie out a few weeks ago after a couple of months of it not moving very far

The brakes seemed fine for the first part of the run which took around 30 mins or so. i then set off again and the brakes were ok for about another 10 mins, but then the brake pedal was travelling to the floor!

The brakes did work when i pumped then, but every time I hit the brakes the first time it went to the floor.

The following weekend I bled the brakes with my gunsons eazibleed (was impressed with it!)

Went out in the car, first 20 mins, brakes were fine

Then, my foot started getting nearer and nearer the floor again

Today I changed the master cylinder

Been through almost 2 litres of brake fluid this weekend and last weekend

Put braided hoses on

Took her out. Exactly the same problem. Brakes ok for the first 10 mins or so, then pedal travelling to the floor. Can anyone help?
There is also a clunking noise on the front left side under braking, which only seems to occur when the brakes get bad.

Is it calipers?

As you have replaced the master that should be fine. Guess the caliper seals need checking next, any fluid evident, other than spillage from bleeding? Use a Gunson's connected to the compressor myself, regulated low, great little bit of cost effective gear?:

Can't find any leaks

I am thinking that if it was a leak, wouldn't the brakes be crap as soon as I get in the car, and not after 10 mins of driving as they seem to be?

Really stumped

Are the brakes binding and heating the fluid .....


Unlikely but if one of your hubs get hot it might be the cause

No all the wheels seem free

Really stumped

Might be a trip to Peak Alfa

Still stumped Jools
Where did the master cylinder come from?, it's been mentioned before, but there is a faulty batch about I had much the same problem AFTER I fitted a brand new M/C. I sorted it with a replacement M/C which wasn't brand new, but still in good order.

The clunk is more than likely the front Caster Arm bush, a problem I'm all to familiar with at the moment!.

http://i88.photobucket.com/albums/k1...s182/br011.jpg

I got it from Classic Alfa, still got the brake problem!

There's definately a bad batch of single circuit M/C's around, but I'm not sure about dual circuit ones.
Sorry I'm not helping here am I....

When you bleed the brakes, are you seeing air bubbles in the fluid? That should help you isolate the fault to one wheel (or wheels). The fact that the brakes work when you pump them indicates air in the system.

I did have a similar problem a long time ago on an Escort Mexico, caused by air being drawn past the rear piston seals on the pedal return stroke, which I cured by packing the cylinder boots with red rubber grease (still got loads of it!), but unless your calipers use drum-brake type piston seals rather than the normal disc brake square-section seals that's not likely to be your problem.

Not much help, was I? Meanwhile, any Berties I see driving around locally will be given a wide berth!

Stay behind them Dave
Shouldn't be a problem in a 145...

I am thinking now that it could be the brake fluid getting hot

When I have had the car up on stands, all the wheels moved freely, but I went for a run today and one rear did seem a bit hotter than the others

So I might have finally sussed it. Now I have to fix it

Keep at it

You know it'll be worth the effort

I've just had problems with a sticking piston in my front offside brake caliper. There was no loss of fluid but it was noticable that the car was pulling to one side and a bit sluggish.
Take one brake pad out at a time from the suspect wheel, get someone to slowly press the brake pedal an watch to see if the piston moves freely out of the caliper. If it does move freely, lever the piston back so you can get the brake pad back in and then try the other pad.
I had one piston sticking and with working it in and out I hope I might have got away with having to stip the calliper down.
Good luck!!!

Originally Posted by VeloceMitch

Stay behind them Dave
Shouldn't be a problem in a 145...

With brakes in general Dave, it needs to be a start to finish, approach,rather than a 'one off' reason for malfunctions. Full system overhaul maybe?:

If a piston is trying to seize, in my experience, there's no liklihood that trying to free it by moving it back and forward will succeed. The caliper will need to be rebuilt, polishing out the rusty bores, and then change the fluid regularly to combat the moisture-absorption problem, or consider silicone fluid.
Did you eliminate the possibility of the pads 'walking' back or being pushed back, creating a long pedal? Is your car discs all round or drums at the rear?

I think Silicon fluid is a no no with these cars, not sure why but everybody seems to avoid it.

I have read of seals apparently affected by it on here. Not heard about it anywhere else. I must say I've tended to assume it it's pretty benign as a chemical so not expected problems. I committed the ultimate sin recently and put it into a system that previously had normal stuff in it. Fingers have been crossed since.