Vibrations under braking, before and after KADs

[Beastlee]

Oh...and brakes.....

You say you've had a wheel bearing done - which side?

Also, you've replaced a lot (a LOT) of stuff trying to fix this vibration - can you confirm what you've changed AFTER fitting the Kads, as I suspect we need to disregard everything relating to the brakes before that point.

So it's Freshly rebuild calipers, all bolts, new disks and pads, isn't it?
And one side has had a wheel bearing done.

How bad is this vibration? Does the car shake or the steering? Does the wheel pull at all?

Since fitting the KADs I've done both lower arms and that's it. I don't know which side was done in the way of a wheel bearing as they are universal and it was the previous owner. There's definitley no play in anything and I suspect the knock is now the ARB bushes, this is based purely on the fact we've just done the ones on the Delia and cured exactly the same noise.

I've bought a set of female torx sockets and I'm going to double check the torque on all of the bolts holding the discs onto the bell housings. I suspect it may be something to do with the discs as the vibration was never this bad on the old brakes, in fact it was only present under heavy braking. I remember when I first fitted the new wheels commenting how much better the braking felt.
At 40mph the vibratioon makes the whole car shake a fair amount and it is uncomfortable under foot and hand. At higher speeds it is present but no longer uncomfortable nor excessive.
If I have screwed up when mounting the new discs onto the bellhousings am i likely to have done permanent damage to them? I assume that heating them up when not perfectly true won't have helped matters.

[Turbo_Steve]

Potentially - Yeah.

[Beastlee]

Bugger. Oh well, if they're goosed then I'll have to live with the vibrations as I'm not buying some more at £450 a set!

[Turbo_Steve]

If they are, then you might MIGHT be able to get them sorted out at a decent enginineering place.

Something to do with heating them up and resetting them...not sure how it works, though.

[Beastlee]

Was looking for a dial gauge and suitable stand but they ain't cheap. Hopefully I can check them out tomorrow.

[Beastlee]

OK, so I finally managed to get the discs off and double check the mounting bolts. Everything was loosened and put back together to the correct torque and pattern including the calipers and wheels. All surfaces and bearings were checked for play and came up good as well as the track rod arms.
I think the vibrations were slightly less and are definitely stronger between 40 and 50 but I also noticed that there is nothing through the wheel it's all chassis and brake pedal.

[fluffnik]

I think the vibrations were slightly less and are definitely stronger between 40 and 50 but I also noticed that there is nothing through the wheel it's all chassis and brake pedal.

Could it be bushes?

Do you get smaller version of the vibration at similar speeds set up by corrugated surfaces?

There's a somewhat similar problem with BMWs which is down to a hydraulic bush that's compressed by braking (or by driving over corrugations) going off...

Can't think of a likely culprit in the Legnum suspension though.

[Beastlee]

It's more of a shudder rather than a pulse/rumble as I would describe what you mention. There's no feeling like the ABS is going in and out either, the braking power is consistent and strong.

[fluffnik]

It's more of a shudder rather than a pulse/rumble as I would describe what you mention. There's no feeling like the ABS is going in and out either, the braking power is consistent and strong.

Yes, the BMW problem is more of a pulse and is felt through the wheel too...

Hope you get a solution soon.

[Beastlee]

as long as it's not the start of any kind of mechanical failure I can live with it I suppose.

[Beastlee]

OK, I've had a couple of updates today, one about the brakes and the other my electrical fault.

I finally phoned KAD about the brakes and they reckon it can only be the discs and or bellhousings causing the issue. It looks like my next move is going to have to be a DTI. Will have to see if anyone here has one before I go buying one as I'll not need it again I wouldn't have thought.

The dodgy headlight issue had reappeared as well as flickering lights at tick-over. The battery health indicator had gone black again which didn't seem good for a week old battery. Metering it with the car running only gave 12.8V and didn't change as I raised the revs. It was then that I figured there must be a loose wire and started to wiggle the earth, nothing happened so I wiggled the thicker positive wire, still nothing. I then moved the smaller positive wire and bingo the voltage went up to 13.9V and all the issues disappeared. When I replaced the old battery I had to replace the clamps and in order to fit the new one I had to fit the ring connector under a screw down terminal. It seems the screw had loosened very slightly, enough to let the ring move and reduce the contact area such that it wasn't passing anything to/from the battery. I've not looked at the wiring diagram yet but I suspect this has been an intermittant fault with the charging circuit that has been draining the battery and only putting the minimal charge back in. Hopefully that's done with for now.

[Beastlee]

Thought I'd close this one off. The brake issue seemed to be resolved once I amended the KAD designed mounting brackets to actually clear the hubs immediately followed by a repeat bedding in process.

The power issues turned out to be the smaller wire from the battery had actually come loose, although to look and test it wasn't apparent. Once it was secured all my power problems vanished.