11 replies to this topic

[Camel]

On the way home tonight I noticed that when taking a right hand corner pressing the brake pedal did hardly anything compared to normal and the pedal was very soft. Then I needed to pump the pedal once or twice to get the proper feeling and braking back.

 

I tested it on a left hand bend and it was similar but no where near as bad. If I've not turned for a while then the brake pedal feels fine, it only happens when I've recently gone around a corner. The tighter or longer the corner the softer the pedal gets.

 

Any ideas what could cause this?

[rally515]

Cut off of supply on the flexi hoses ? check them to see if there kinked or something

[Ethel]

Wheel bearing,

 

It's allowing the disc to push the pistons back in to the caliper. That or the fluid level is dangerously low in the reservoir.

[Captain Mainwaring]

Ethel has nailed it...with wheel bearings knocking the pads back.

[tiger99]

I concur, definitely pad knock back caused by worn wheel bearing. In fact this is almost a textbook example of it and its diagnosis. Usually the symptoms are not quite so clear.

[Gulfclubby]

I have had a somewhat less obvious cause for similar behavior. My bottom shock absorber bolt had broken off without me noticing and the shock was dangling around, shearing through the flexi hose just enough so that under a certain angle it would leak (when cornering), but not in a straight line. I noticed quickly when there was hardly any pressure and the problem was fixed quickly. Do make sure your brake hoses are in good working order and you have no leaks. Checking the bearings at the same time will be just as easy.

[Cooperman]

Check that the centre hub nut is tight and the split pin is in place.

[Camel]

Ahh, bearings. That does make sense as I know they need replacing and had planned on doing them as soon as possible.

 

I think I'll order some new brake hoses and get some new brake fluid along with a calliper seal kit. May as well get them all done at once.

 

Thanks for the help everyone.

[Captain Mainwaring]

I have had a somewhat less obvious cause for similar behavior. My bottom shock absorber bolt had broken off without me noticing and the shock was dangling around, shearing through the flexi hose just enough so that under a certain angle it would leak (when cornering), but not in a straight line. I noticed quickly when there was hardly any pressure and the problem was fixed quickly. Do make sure your brake hoses are in good working order and you have no leaks. Checking the bearings at the same time will be just as easy.

 

Yes, brakes are important aren't they? One's life could depend on them. Always pays to check everything very thoroughly and moreover....never give duff and dangerous advice regarding brakes or indeed any part of the car.

[Carlos W]

I have also heard of a loose hub nut causing these symptoms, I was a passenger coming into paddock hill bend at Brands Hatch on a track day at the time!

Either way it needs sorting before it gets driven any more!

[tiger99]

Well, a loose hub nut is effectively a bearing problem, because it makes them sloppy, although it is worse than just that, as it also allows the drive flange to wobble on the shaft.

 

If a car of any sort has been run with a loose hub nut it is advisable to change all the relevant parts, in this case bearings, hub flange and CV, as they will all have suffered unusual wear.

 

However, in this case it will hopefully turn out to be worn bearings only, with no damage elsewhere.

[Camel]

Yea, I'm going to be checking everything as it all needs to come off anyway for ne CV boots. I'm just glad it started happening after midnight when there were no other cars around. And don't worry, I'm not stupid enough to drive a car with sub par braking!

 

The split pins are on the hubnuts but I'm not sure how tight they are set. I'll probably find out tomorrow when I get the new stuff put on weather permitting.

 

I suppose I'll have to stick to driving a modern car for a few days though.