FIXED: Rumble / knocking noise from front

[davesmith84]

Hi all, I've recently rebuilt the front end of my bus which was running a King and Link pin beam, I've gone back to a stock ball joint beam but with adjusters and everything was fine. Did a trip to Cornwall and back with no issues or naughty noises.

I decided to grab some French Slammer dropped spindles from machine 7 (which are awesome BTW) and since putting them on I've had a rumbly / knocking noise at anything above 10mph ish. It's probably best described as a burble or a rumble type of knocking - I've had a loose shock and even a loose caliper before, it's that kind of sound.

The first thing I did was remove both shocks and go for a drive - the sound is still there all be it a bit different sounding??? A bit 'duller' sounding??

I've checked all 4 ball joints - were new when the beam went on which is less than 1,000 miles ago so they're fine. I also ensured the nuts are tight too.

Checked callipers - these were also changed from 71/72 only callipers to late callipers in order to fit the French Slammer spindles. I've checked they're tight. I did have to buy new bolts for the callipers and I've put the shanked bolt in the upper holes as that what the interwebs seem to favour although, the Bentley manual does say the shanked bolt should go in the lower hole!?

Checked track rod ends on the spindle - intially I thought I'd solved it as the original, stock track rod ends from the stock ball joint beam seemed to be narrower than the spindles' tappered holes. I ensured they were seating properly using a couple of washers to allow the nut to pull them through futher. I even removed the boot to make sure it was seating properly. I'm confident they are now and that there's no play there. I'm not aware of needing over sized track rod ends with these spindles?

I've checked both bearings, each side. Again, new bearings were installed when the beam went on.

I've fully greased the beam.

I've basically checked anything that I would have removed when swaping the stock spindles for the dropped spindles. Come to think of it, the only other thing I did was raise the beam on th adjusters - I'm racking my brain to think if I undid the track rod ends at the steering arm end... hmmm I'll defifnitely check that tomorrow. Maybe I didn't get one quite tight enough? I also had to heat my adjusters up to get them to shift. Pretty sure that wouldn't have damaged anything though? Please correct me if I'm wrong!

My next check over was going to be all the steering linkages although I don't feel anything through the steering wheel when I hear the noise but I do feel it through my feet a little.

So, thanks for reading and I'm most grateful to anyone that can give me any suggestion to what they think it can be!

EDIT: one crazy thought I had was that maybe the shock(s) was slightly loose or even knackered which was causing the initial sound but now I've taken them off I'm just getting the 'un-tamed' sound of a beam with no shocks?? Has anyone driven a mildly lowered bus with no shocks? Does it make any weird sounds!? I know this is a bit of a stretch but I'm baffled!

 

[Moseley]

Have you jacked it up and spun the wheels independently? A rumble would suggest a rotational noise, which narrows it down to wheels bearings / brakes / something in that area.

Wheel bearings not over-tightened are they?

 

[davesmith84]

I've had it jacked up, down, even left and right! Ha! I've spun the wheels, pulled them in and out, left, right, top, bottom etc. the one thing I haven't done is had to bus on axle stands whilst jacking up from under the lower torsion arm to the point where the jack is taking all the weight of that wide and then push/pulling the wheel around. I've read this can be really useful when trying to find worn ball joints etc. will try this tonight.

Definitely not over tight bearings. I tried them nipped up tighter than they were then I also tried barely nipped up at all, just enough to take the play out the bearing.

Rumble probably isn't the best description to be fair. It's more of a constant knocking at a frequency that is almost a rumble and it's not very loud either.

It's consistent with small bumps in the road too. Definitely sounds like something in the suspension/steering is slightly loose and it's knocking/rattling around.

Thanks for you suggestion, I will definitely double checked what you've said later this evening when I can get back under the bus. Cheers.

 

[VeeDubMan]

One other thing to check is worn bearings in the torsion tubes causing the arm to move around excessively in the tube. Grab hold of the wheel top and bottom, wiggle back and forwards and listen out for/look for any movement. Also check for worn/loose steering idle pin

 

[davesmith84]

Thanks mate, yeah, worn needle bearings was on my mind. I will check that too.

I will definitely check the steering idler pin too when I'm going over the steering linkages tonight.

Thanks chaps.

 

[davesmith84]

I am fully stumped with this one!

Checked over everything again tonight and everything looks fine. Had the spindle jacked up with the weight of the bus on them and couldn't get any kncoking noise from pulling the wheel around.

I even took the steering damper off to rule it out.

Here's a very short video of the noise - it's loudest at the start of the video.

https://www.youtube.com/watch?v=zF7RhUbHxqk

Any more suggestions GREATLY appreciated!

 

[Moseley]

That doesn't sound like a loose suspension kind of noise to me, more like something flapping around and rattling against the chassis.

Are you sure it's from the front? Horn loose? Have you tried bouncing around in the van / shaking it vigorously whilst it is on the ground to see if you can replicate it?

 

[davesmith84]

Could be, I suppose. Although, it is quite a deep bassy sounds as you can hear in the video which would suggest something more substantial?

I've tried shaking and rocking the van by hand myself but I couldn't hear anything. I think the next step is to get the Mrs to bounce around in the van (that's what she said) whilst I get my head under it to have a good look.

By the way - in the video there is a single knock sound around the 3-4 second mark - that's not the sound I'm on about, that sound is my steering box - becauase I've removed the damper it makes a clunk noise when to wheels are pulled sharply in a direction, like a bump or pot hole.

 

[VeeDubMan]

If your misses bouncing around inside doesn't help, how about taking it to an MOT test station where they can put it on their wheel wiggler thing and take it from there?

Just a thought

 

[davesmith84]

Well, the mystery continues.

My mate popped round and he gave the bus a right good shake and we couldn't replicate the sound. When we drove it, it feel like a wobbly knocking when the wheel is shocked upwards which is a hard movement to apply to the wheel when trying to diagnose.

I then got the buss on axle stand under the beam, jacked each wheel up via the spindle arm then checked the wheel 12-6 and 3-9 positions, no play what so ever. I even put a pry bar under neath the wheel to see if there was any vertical movement (this should diagnose play in the ball joints I believe) still no play.

I literally have NO idea now!?

 

[Moseley]

Have you tried wobbling the steering components underneath the van? Idler pin - is that correctly preloaded with the sprung washers? Try turning the wheels lock to lock to see if it moves up and down at all as this can happen as they wear. Could also be worn bushes within it - are they well greased?

 

[davesmith84]

FIXED!

Turns out it was a combination of three things:

1) Loose shock(s).
2) A ball joint beam make some knocking noises when it has no shocks on it.
3) Stupid owner.

Like I said in a previous post, the sound started out very much like a loose shock but then the sound changed when I removed the shocks. Well, I had checked literally everything more than once so I thought I'll just put the shocks back on as they did make the sound change. Hey presto, no more knocking.

So the initial problem was a loose shock but when I removed the front shocks the sound seem to get 'duller' sounding. So it seems a ball joint beam does have a dull knocking sound when it doesn't have shocks bolted up? Maybe I should be worried that there is a problem that is causing the knocking and putting the shocks on (correctly bolted up!) is simply masking the issue BUT I've been over every inch of the front suspension and I know nothing is loose or has any play; I'm happy to the run it like this for now.

It does make perfect sense as the sound would occur when ever there was a minor shock to the beam, like going over a rough surface on the road.

Be great if someone could confirm that beams make weird noise when ran without shocks!? Anyone prepared to take their front shocks off and go for a drive!?

Thanks for all your help guys!

 

[VeeDubMan]

I'm trying to establish the same thing, but I believe there should only be rotational movement of the trailing arms on the needle roller bearings; any knocking could indicate worn bearings/worn trailing arms. I've replaced the bearings on my Red 9 Design beam (which are not standard VW ones but HK5020) and still get some movement. Only options left for me are worn trailing arms...or beam, but it was brand new so wouldn't expect this.

Take a look at http://forum.earlybay.com/viewtopic.php?f=4&t=65350" onclick="window.open(this.href);return false;

 

[davesmith84]

Sorry mate, I'm not familiar with the Red9 stuff at all.

What I will say though (having read your thread and watched you videos) is that no matter how much I pulled the wheels around, whether jacked up a bit, a lot or down on it's wheels, I couldn't get any play in anything, especially the torsion arms. What your arms are doing is pretty scary! It's almost like the beam doesn't have the inner bushes (I think there's machined metal collars, fixed to the inside of the tubes, set just inside the tubes to hold the inner arms - I'm not 100% certain on this though).

EDIT: Yes, you can see in these pictures that there's an inner collar that holds the inner part of the arm.
http://www.thesamba.com/vw/forum/viewtopic.php?t=64301" onclick="window.open(this.href);return false;
Maybe worth checking your beam has these!

 

[VeeDubMan]

Maybe worth checking your beam has these!

Yeah, they're definitely there as I have to wiggle the arm through them to get the arm fully in...which takes some patience with the grease!

Got a reply from Red 9 Design anyway, so we're hopefully on track to getting it fixed.

 

[davesmith84]

Ahh great stuff, best of luck. I've subscribe to your thread so I look forward to hearing when it's fixed.