Front suspension knocking

Gargo

Gargo

Active Member
Hi all,
2nd problem found on a fast test drive. I'm getting a knocking from the front right corner. We have always had a knocking from the front right but we could never find the problem.
Tonight with the car gripping better than ever the knocking is worse. However I think I've found the problem.
dsc00594.jpg

Here you can see the steering 'slide rod' to Swivel pillar ball joint rubbing on the inner arch. The photo does not make it clear how much bare metal there is.
Is this a known problem?
What can cause it, is it just the play and deflection of the suspension components or is it more?

Thanks,
Gavin.
 
I can't remember ever seeing a siderod hitting the inner wing so I think there must be a lot of play in something somewhere, or the front of the car is out of line.
 
Hi,

It's hard to tell under the mud of various competitions but is that the edge of the “Australian” strengthening kit? Just where the contact seems the worst? I think a good solid wack with a clearance maker is what’s needed :oops:

Tim
 
Yes Tim I was wondering if the strengthening kit when that high. There is a weld seam so that must be it. If the clearance maker doesn't work I get a heaver one. :evil:

On this car the top link bushes went a long time ago and we replaced them with Nylatron machined to fit. So I hope it is not this. I think it is telling that we have always had the front left knock, so clearance was always a problem, (ref the strengthening kit) but why it has suddenly got worse I can't think; other than play somewhere. I'll give it all a good check.
It maybe a good excuse to play around with the front suspension, there is just too much rubber.....
Gav.
 
Hi Gav,

I have seen that a few times before on cars here in Australia. Apart from the strengthening kit, how is your steering idler? Does it have a lot of free play? Has anyone ever altered the camber?

Ron.
 
Hi Tim and Gav

Lucky also has the Australian kit and is driven quite as hard on occasions, as your car. No contact as yet after some thousands of miles though.

My money would be on some looseness in the top link bushes. You'll probably know that I have the experimental Alan Ramsbottom bushes there which are, loosely, machined nylon around the OE steel sleeves. These have been a disaster, as they are unable to accept the rotational torsion and conseqently rotate in the housings. At the moment this translates into severely annoying clicks as they move, but no obvious dimensional damage. It may be that in your use environment, with a lot more road muck around, that yours have worn rather more. If that were the case then you might expect some side to side movement in the front, top balljoint, end of the top link. This might not show up static, but if it did you would observe onset of some slight negative camber due to the uporight being in the correct place at the bottom, but a tad inboard at the top.

For this reason, I would advocate using standard oe rubber bushes in the top link location - available from JRW. This because the polybush equivalents are lacking in the steel sleeves and are again unable to accept rotational torsion. Any loss of precision over something harder I think is more than compensated by robustmess in use. Otherwise I'm with you completely on toughening up the remaining front end bushes!

Ron's diagnosis of the idler is possible, but would be more likely to show up on the left side.

The other possibility is looseness in the top and bottom ball joints on the pillar. As discussed elsewhere, this can be very difficult to identify because of the way the suspension is loaded, even with the road wheel off the ground.

Hope that helps.

Chris
 
I have the same issue, in my case only only on the passenger side of my '72 3500. The extra plate in the chassis stiffening kit effectively thickens the wall thickness of the wheel arch, and I've noticesd that the rubber boot of the top ball joint has rubbed away the black schutz, and also the grey seam sealant that I applied to the top edge of the stiffening plate. There is a very obvious witness mark.
In my case all the bushes in the front suspension, including both inner and outer top link bushings, have been replaced with new purple urethane items with steel sleeve inserts. There isn't any play anywhere, the ball joints in the swivel pilars are also new.
I had been thinking about dressing the weld and the stiffening plate down a little with the angle grinder, but am a bit loathe to remove material, having gone to all the trouble of adding the stiffening there intentionally in the first place. Looks like a tight fit for the power tool too with everything built up. Don't really see how I could swing a 'clearance maker' ( :LOL: ) in there without first dismantling the suspension either. :(
I'll snap some photos later for comparison. Very interested to hear suggestions for addressing this issue. I don't rally my car (yet!) but I like to drive it like I stole it, on occasion.
 
chrisyork wrote,...
Ron's diagnosis of the idler is possible, but would be more likely to show up on the left side.
Click to expand...

Hi Chris,

The photo that Gav posted is of the N/S (left hand side), although he has described it as being the right side. I expect he is referring to the side as when viewed from standing in front, as opposed to the correct convention of being seated in the driver's seat.

Ron.
 
OK left, right yes all depends on if you are sitting looking forwards or looking out the rear window with no seatbelt on :LOL:

Left side that is the opposite side to the steering wheel, if it is on the right. :LOL:

Anyway, I bashed the inner guard away, boy it's solid, but the problem was the nut who tightened the nut on the end of the front upper rocker didn't have it tight. :oops: You can see in the before and after photos the rubber is not crushed and once I got the nut tight up against the rubber's steel insert the rubber is now crushed much more. As the full lateral load path from the upper rocker is from the washer through the rubber to the baulkhead mount, this is where maybe just 1/16" of play resulted in the balljoint fouling the inner wing.
Loose nut:
dsc00619.jpg

Tighened:
dsc00629.jpg


P.S. that nut was me. :oops:
 
Thanks for posting those pics Gargo. I took a closer look at my front suspension, lo and behold, my outer bush wasn't fully tightened up either. :roll: I removed the front bumper and took of the front wing to get proper access, and tightened it up, I hope, sufficently. The gaitor on the passenger side steering rod ball joint has expired, from where it has rubbed back and forth on the top weld of the chassis stiffening plate.
scuff-mark-from-steering-rod.jpg

The scuff mark is very noticeable. The silicon seam sealer has been removed exposing the weld.
scuff-mark.jpg

passenger-outer-link-bush1.jpg

bushing-tightened-up.jpg

The outer bush before and after being tightened up properly. Before, hardly any thread can be seen beyond the nut. Now a cm of thread is visible on the swing arm.
new-gaitor-scar-repainted.jpg

Scuff mark repaired.
I sourced a suitable ball joint gaitor and refitted the steering rod. I primered and then stonechipped over the 'scar'. I will test drive, turning on full lock either side, to see if it scrapes a new witness mark, before I reassemble the wing and bumper properly.
Still might have to hammer the stiffened wheel arch/engine bay wall inwards a bit...
 
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