Cheap fix for faulty ABS modulator on VR

[Calaber]

Another post regarding ABS repairs reminded me of a time a few years back when my son's
VR Acclaim developed an ABS fault. To put it simply, the brakes became incredibly heavy to apply - similar to having no power assistance but perhaps even heavier.


We did the usual checks - vacuum hose, vacuum valve, siezed calipers, disconnect booster to see if brakes were the same with and without assist - no success. The fault was intermittent, but no ABS fault was showing on the dash and no messages in the computer.

This went on for a few weeks, sometimes the brakes were fine, other times they were good when cold then "siezed" after a few k's.

The young bloke got the shits with the thing one day when they decided to bind up again. He stopped the car, and stamped the brake pedal about four or five times as hard as he could in sheer frustration.

Fixed the problem, didn't it? Never recurred until he sold the car about a year later.

[bandit10]

wonder if there was a air lock in the ABS module, when you bleed the brakes on ABS models you can plug a tech1/2 in to them to cycle the ABS system to get air locks out.

I wonder if his "sheer frustration" stamping on the pedal moved an air lock..?!?!

Just an idea.. sounded good in my head lol

[Brett_jjj]

wonder if there was a air lock in the ABS module, when you bleed the brakes on ABS models you can plug a tech1/2 in to them to cycle the ABS system to get air locks out.

I wonder if his "sheer frustration" stamping on the pedal moved an air lock..?!?!

Just an idea.. sounded good in my head lol

I was thinking along the same lines as you..trapped air,and the big stomp on the pedal pushed it through.

[bandit10]

*high five* lol

[ParkwayDrv]

for some reason I'm doubting this will work

[Calaber]

for some reason I'm doubting this will work

What is it that you are doubting?

[immortality]

a airlock would give a spongy pedal feel with more pedal travel

[RX25SE]

As above, I don't think it was air.
More likely a blockage in the module. This may explain the 'siezing' brakes, and a hard stomp may have dislodged it.
The modules have fine gauze filters in them (not serviceable) to protect the vaves inside the unit.
Important to keep the fluid clean and fresh with ABS brakes!

[Calaber]

As above, I don't think it was air.
More likely a blockage in the module. This may explain the 'siezing' brakes, and a hard stomp may have dislodged it.
The modules have fine gauze filters in them (not serviceable) to protect the vaves inside the unit.
Important to keep the fluid clean and fresh with ABS brakes!

Yep, that's what I think it was. I forgot to mention that we had also bled the brakes and there was no sponginess. That was the odd thing - the system was able to be bled, so any blockage didn't hinder free flow of the brake fluid. I believed the problem with somewhere within the ABS module, but the diagnosis section of the genuine VR factory manual which I had at that time didn't cover the sort of problem we were experiencing. I looked a number of times at the exploded diagram and cross-sectional diagrams of the module in the manual, and felt that a siezing piston or valve had something to do with the problem.

This would have to be the only time I have ever seen losing one's temper being the appropriate fix - it's usually quite the opposite.

[Brett_jjj]

Yeah agreed,would not be air if the pedal was hard.There is pistons and bores inside the actuator,the pistons were probably seized up in the bores(probably caused by bad maintainance).The hard stomp might have freed them up.I have seen a few low spongy pedals on ABS vehicles though.Air gets caught in the ABS system.The only way to get it all out is to use the ABS brake bleed feature on a scantool(Tech1/Tech2).The scantool cycles the ABS system so trapped air can get out.