Strange Braking issue - EF Fairmont Wagon

[SPArKy_Dave 8,870]

Got a weird one with the Silver EF Fairmont wags project I did for my cousin.....

 

Occasionally, (and only at really low speeds coming to a stop when parking with the wheels turned),

it feels like the ABS is applying.

The brake pedal pulses slightly and rapidly underfoot, and you get an oddball groaning noise, accompanied by a 'twanging' sound like a gate spring extending/contracting.

 

Partly due to the above, and partly due to warped front discs, I rebuilt the front brakes - new QFM HPX pads, DBA 4132 slotted discs,

Genuine Timken bearings and OEM NOK hub seals.

 

I also rebuilt the front calipers, using genuine Ford/PBR caliper seal kits, new Genuine PBR pistons and new Genuine Ford stainless steel anti-rattle pad slides.

 

Fitted 4 new Genuine Ford caliper bleed nipples, then flushed the whole system using 2ltrs of Genuine Ford DOT 4 brake fluid.

Standard QFM pads were fitted to the rear and the caliper slides were checked, but didn't touch the rear discs or calipers themselves.

 

 

I was really hoping the brake caliper rebuild and fluid flush, would fix the issue... but it hasn't.

Anyone experienced the above phenomenon before?

 

It feels like its coming from the front, but anything's possible at this point.

My next test, was to maybe disconnect the ABS, and see what happens - in case it's a faulty wheel sensor or something weird like that.

 

After the brake system rebuild, the phenomenon seems to be occurring more frequently.

 

PBR ester based rubber grease was used on the piston and piston seals.

High Temp Silicone grease was used on the caliper slides.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Outback Jack 6,352]

Hey mate, I dont like the look of those pistons.

Its the leading edge, should be nice curve to it. Looks like its been coming out/retracting unevenly.

They were pretty badly pitted to start with, did they clean up ok or still have pits? Tolerances are pretty fine on those pistons.

Jack up front as well and wiggle wheels, sometimes after new bearings they take a lil bit to seat and need readjustment.

Or the pads weren't loose enough when doing bearings, making them feel tight when in fact they are still loose.

Just few ideas.

 

Jack.

[SPArKy_Dave 8,870]

New pistons were used.

I wasn't going to re-use those pitted things.

 

The wheel bearing pre-tension was set without the brake calipers even on the car.

 

Also, it was doing the thing, before I did any work to the braking system.

[jca25 1,034]

try the left hand abs wheel sensor clable i know on the later models it causes that fault but have never came across that on a ef but

[Mikefpvgt 1]

Hi mate I'm having the same problem with a BA falcon did you end up working it out

I have changed booster, master cylinder,abs unit,

Any help would be greatly appreciated 

[SPArKy_Dave 8,870]

No, the problem hasn't been worked out as yet.

The vehicle hasn't been used much the past few years, so it hasn't been given priority.

 

My thoughts are, it's ABS engagement, due to the ackermans angle wheel speed effect -

ie, when making left turns,

the inside (left) wheel's, rotate less than the outer (right) wheel's - which rotate more, as they travel in a larger arc.

 

I reckon my issue is likely an ABS wheel-speed sensor/sensitivity problem.

It only ever occur's at very low (carpark) speeds.

 

[Mikefpvgt 1]

Thanks for the reply yes mine does the same,i have replaced the 2 front speed sensor with one's from my other ba will do the rears tomorrow starting to think it's a communication problem between the pcm and abs module it did throw a can bus code at one stage U1900 if i have any luck will let you know

Cheers Mick