Defeated by the brakes

[David Lawrence]

Changed the front left caliper a while ago, and suffered a “softer” but certainly not spongy pedal ever since.

Brakes normally, but when braking from motorway speeds there is a discernible twist to the right when first applying the brakes. On soft gravel, the right side locks up. All telling me that the side with the new caliper is still not properly bled.

Ive now tried vacuum bleeding, all that seems to do is suck in air from around the nipple once loosened. I got a slightly better result with it, but the slight pull to the right remains.

Tried pressure bleeding, flushed through a good 300ml of fluid through it, but still no change.

I have repeated this process now at least 10 times. No air comes out, only fluid.

Never had a car I couldn’t bleed before now. Looking like its going to be left for Jules to sort now. 35 years of maintaining cars, never been beaten by the brakes before.

[slovcan]

Originally Posted by David Lawrence

Changed the front left caliper a while ago, and suffered a “softer” but certainly not spongy pedal ever since.

Brakes normally, but when braking from motorway speeds there is a discernible twist to the right when first applying the brakes. On soft gravel, the right side locks up. All telling me that the side with the new caliper is still not properly bled.

Ive now tried vacuum bleeding, all that seems to do is suck in air from around the nipple once loosened. I got a slightly better result with it, but the slight pull to the right remains.

Tried pressure bleeding, flushed through a good 300ml of fluid through it, but still no change.

I have repeated this process now at least 10 times. No air comes out, only fluid.

Never had a car I couldn’t bleed before now. Looking like its going to be left for Jules to sort now. 35 years of maintaining cars, never been beaten by the brakes before.

Hi David,

I have had to replace a bleeder screw before that would draw air in past the threads. I could get it firm, but not hard . Stop that! The brake pedal or, in this case, the brake lever.

Cheers,
Glenn

[COLVERT]

Maybe, just maybe. The air you are chasing is not in that caliper.---

[bl52krz]

Originally Posted by COLVERT

Maybe, just maybe. The air you are chasing is not in that caliper.---

Are you thinking what I am thinking? ABS?

[3disco]

Bleed with a t4?

[David Lawrence]

This car has had slightly less than excellent brakes ever since i replaced the front to rear pipes in about 2010, and i got it to an acceptable state then just got used to it, but always felt the pedal was slightly soft.

It was only when i got the second car and had a direct comparison that i can tell its certainly not totally free of air. That car had a few caliper refurbs done by Jules recently and it came back rock solid pedal so i know how it should be.

It is possible that the air is somewhere else in the system, but have bled all 4 wheels and the symptom stays the same.

[slovcan]

Good info. Obviously these cars don't have limited slip differentials.

Thanks,
Glenn

[RoverP480]

I had a problem with air in the ABS modulator on a BMW motorcycle. A number of sessions involving braking hard on a damp road and invoking the ABS operation , and then bleeding the system again, eventually pushed the air out of the modulator into the main lines and then out at the bleed screws.

[David Lawrence]

Originally Posted by slovcan

Good info. Obviously these cars don't have limited slip differentials.

Thanks,
Glenn

I could have air in my abs module, but my symptom is of air only in the front left brake. I had the hose clamped while i changed the caliper, and bled the new caliper straight away. It is the front left wheel that is weaker braking force, so all adds up to air still in the caliper. Should be a simple job, the fluid flows through easily, pumping the pedal also easily to the floor confirming no obstructions. Just cant get enough through to carry the air out.

[Avulon]

Did you fill the new caliper with the pistons fully extended before pushing the pistons back and fitting? IME it's no good fitting a 'dry' caliper to a brake line and trying to bleed the air out, you'll never get all the air out.