The dreaded knock on minor bumps

[manoman48]

I wish I knew more about suspension and steering setup, then I might understand where its coming from. Getting a knock going when driving over poor roads at slow speed, so guessing its a drop link?

In tomorrow for investigation so will see what they say. Not much point to this post, but its the first thing to go wrong on my T4 that I don't feel able to sort myself.

[JSeaman]

Can be a pain to track down these sort of problems. Have you checked the wishbone out? Bushes could cause knocking on bumpy roads. There's also the CV joint which could cause you problems

[manoman48]

I had the balancing done last week as the steering wheel is shaking at over 70mph. If anything the shake got worse so that concerned me. That said they used the weights that stick on the inside of the alloy rather than hook over the outer rim (if that makes any difference).

Anyway, it was only driving back from work last night that I noticed the knocks when I was driving over slightly uneven roads at low speeds.

I called the garage where I got the balancing done (a small local independant) and they will be having a good look round tomorrow morning. I really don't know enough about the component names or what they should look like, and I wouldn't be doing the work myself anyway (not enough tools and definitely not enough free time).

I will report back here before getting any major work done to see what anybody thinks. Your opinion would be appreciated JSeaman.

Phil

[JSeaman]

OK basically the easiest thing to do is jack the car up, wrap your arms around the road wheel and wriggle it. See if you can reproduce the knocking. If you can then get a mate to look under the car while you do it and see where there is play

If that doesn't work, get a pry bar/crow bar/long piece of metal and use it to wiggle various parts to look for movement.

The 'wishbone' is shaped like a wishbone (hence the name, it's actually a lower control arm), it has bushes (pieces of rubber) holding it in place. Each place it mounts has a bush and when you wiggle it you might see movement at these joints.

As for CV joint, this is on the end of the driveshaft where it meets the hub of the wheel. They aren't usually much to replace and so you can usually just switch it and see if it cures the problem. Check for split rubber boots around the joints because this lets in dirt and wears the joint.

Hope that helps

[spyda]

To test that the top mount is the cause of the fauly you could try 'packing' it, as the garage did when invetigating mine. I am not entirely sure how they did this but basically they told me they had packed the top mount with rubber and that I should see how it goes.

For all of about twenty miles the knocking was gone and the car felt completely different. I now know that on changing the mount, I will have a much more positive feeling car and moreover, a quieter one!

[manoman48]

Thanks guys. If the garage don't find anything tomorrow morning I will go home and try with those tips myself!

[manoman48]

Well the balancing was re-done by the owner of the garage this time and its is a completely different story. No steering wheel shake at all now. He said it was well out on one side and slightly out on the other. His young mechanic did them for me first time, so may well be getting a rollocking!

Whilst it was up he noticed that the inside of the rear passenger tyre had a chequered pattern on the tread from where the rear shock absorber has not been keeping the wheel on the road. He said this would also cause vibrations but this time from the rear of the car.

Lo and behold, when back on the road with no front end vibration, I can definitely 'feel' the rear wheels bouncing at motorway speeds.

Also all the tyres are 7 years old and drying out, and the front driver's side tyre is on the wrong way round (P6000s).

So today is going to be expensive! Just getting rear shocks done for now while I decide what tyres to go for!

Weirdly enough he didn't find anything with the front setup to suggest where the knock is coming from. The only thing he said he didn't check was the front shocker top mounts.

Given the rear ones are shot, I guess the front ones could be as well..

[mharriso]

mate my top mounts are buggered (they have play but run smoothly), only found it fololowing fitting sport springs, i get a rattly feeling over bumps, on smooth roads its fine though....

also my tracking is out again following a pot hole mating session, it was sweet before that... make sure your alignment is spot on, and getthe rear control arm bushes checked too.. these go and cause rear alignment to go out causing feathering onthe rear blocks..

and so it goes on....

Just put another 5,00kms, i'm up tp 230,00kms, i honestly cannot believe how tight this car is afetr a strip and rebuilt

[manoman48]

Well given the massive improvement to road handling and comfort that the new rear shockers have made, I may well get the front ones done at some point soon. At which point I will ask that the top mounts are checked.

For now though, I am saving for new rubber... Eagle F1s here I come! After abusing the current P6000s that is

[manoman48]

Just to follow this up, I have now had new shockers all round and new rear control arm bushes.

Still got the knock on minor bumps though and looks like this could be the front control arm ball joints as I was shown today that there is some play in them.

Oh and apparently the driver's side engine mount needs doing.

Oh the joys of (rapid) motoring!