Perentie Brake Pedal pulsation

[dingsy]

Hi All,

Since collecting the Perentie I've had problems with the brake pedal pulsating under braking. For background it is the disc front drum rear setup.

So far I have replaced the rear shoes and also replaced the front rotors (one if the fronts was definitely a little warped) but the problem is no better. I don't think the drums are out of round but only had vernier calipers to measure. At 60-70km/hr then braking hard the pulsation shakes the whole vehicle, at slower speeds its only noticeable through feeling the pedal pulsate. The pulsation slows as the car slows.

Is it possible that the MC or booster may have something to do with this?

When coasting in neutral and hitting the brakes the pulsation doesn't seem to occur, however I could be wrong on this as only tested a couple of times.

Not sure if the pedal feels "wrong" in any way as I don't have a reference but the braking is a lot heavier than the D1 disco but thought this is probably normal.

Any ideas?

Most threads on here seem to suggest warped rotors but I've ruled that out already.

Cheers,

Matt

[isuzutoo-eh]

My County with the same brake set up pulsates, it coincided with fitting new drums. It is thus suspected to be an out of round drum on mine. I've heard of others too. Don't rule it out yet!

[isuzurover]

If it is as bad as you say then it sounds like it may be a collapsed wheel bearing or something else loose in the front end???

Failing those options, drums....

[JDNSW]

I recently had exactly the same symptom after replacing the rear drums. I tracked it down to the RH rear brake - jack up and rotate the wheel, tighten the adjuster until it just drags - it only dragged at one spot.

Removed drum, and wire brushed the inside of the drum centre and the hub where they mate, to ensure there was no dirt on the mating surfaces. Also examined the new drum for any burr. Re-installed the drum, and pulled it on by fitting and tightening the five wheel nuts. The brake was then adjusted and checked that it was dragging evenly through a full turn.

Problem solved. Almost certainly a bit of dirt was cocking the drum slightly.

John

[flagg]

... Almost certainly a bit of dirt was cocking the drum slightly.

John

X2 had this recently. It was just a matter of taking them off and cleaning them up properly.

[dingsy]

Thanks everyone, one thing I did notice was that when replacing the rear brake shoes, when adjusting the rear left would stick at a certain point as I spun it by hand. I swapped the drums and the problem stayed on the the same side so I'm hoping a more thorough clean of the mating parts on the weekend might help. I had originally thought that the new pads might just need bedding in.

On a side note, is it possible to have a warped hub?

[JDNSW]

....

On a side note, is it possible to have a warped hub?

Yes, but I can't say I have ever struck one. Similar effect could come from a bit of dirt under the seat of one of the hub bearing races, which would cock the whole hub the same as the dirt under the seat of the drum. But again, I have never encountered this.

The problem is almost certainly as suggested, a bit of dirt or a burr behind the drum, and failing that, there was a bit when the drum was machined!

John

[dingsy]

Well, i've cleaned up the mating surfaces but no luck, brake pedal pulsation is still there. The wheel no longer sticks at certain points when spinning it by hand though so I think it may have helped. I've pulled the drums off and I'll get them machined this week. This should at least rule the drums out as a problem.

Also tried pulling the vac assistance off the alternator - problem was still there as I expected.

The problem does seem to get worse as the brakes get hotter.

[mudmouse]

That's disappointing - so much for the value of the 'blue' slip...:mad: since it's been present since you took delivery.

Hope it's rectified easily (and cheaply) for you.

Matt.

[dingsy]

Problem solved - turns out one or both of the drums were actually out of round. Had them machined and problem gone - thanks for all your help with this guys.

Cheers,

Matt