Pug 306 Rear torsion bar issue

L

lowpugV2

Well-known member
VIP Paid Subscriber
Fellow Frogger
Joined
May 26, 2016
Messages
1,135
Location
Sydney
This car is now testing me. Picked her up from getting the AC fully sorted. Two days ago. Beautiful, crispy cold climate control again.

Then today, driving down the M2 I can hear a funny scrape. Nothing alarming but I get to the Delhi road exit and can smell burning rubber... Hmm, must be the truck in front, those mudguards do seem to be getting caught on his tyres.

Get into Chatswood, truck gone and burning rubber smell persistent. Uh oh. I pull over - car seems to be driving fine - but I'll check anyway.

I inspect all the wheels and find the rear left has been rubbing on something on the inside. I thought maybe some debris stuck but closer inspection revealed what looks to be the innards of the torsion beam pushing a plate into the wheel?? Or is it? I have no idea but the tyre is worn through to the carcass. Additionally, the stability control light has come on, so I guess the abs sensor has been borked.

Any thoughts as to what has happened. The rear beam was rebuilt less than 5000 Kay's ago.
Photos attached
 
Pics IMG_20211201_194731.jpgIMG_20211201_194727.jpg
 
not right for sure, the ARB has a bolt to secure the end pate to it, the end plate itself is held into the torsion bar. Something has let go, do not drive this and fix the rear suspension first, it will fail soon with wheel coming off disastrously. Whoever did the bar needs to correct this.
 
Damn, could have been disaster had the wheel let go at 100kph. I was planning on cautiously driving to the workshop tonight as I'm only 1 kay away. Might just put that on hold....
 
Take the wheel off.

Clean the rubber mess up.

Knock the sway bar end (tear drop shape) back onto the sway bar (its on a spline) and refit an 8mm bolt. If the thread is gone where the 8mmm bolt goes you will need to retap to 10mm.
 
Adrian Wuillemi said:
Take the wheel off.

Clean the rubber mess up.

Knock the sway bar end (tear drop shape) back onto the sway bar (its on a spline) and refit an 8mm bolt. If the thread is gone where the 8mmm bolt goes you will need to retap to 10mm.
Click to expand...
That sounds entirely doable. Thank you. My plan was to take the wheel off tomorrow and have a proper look. Will report back.

Any ideas how that would happen? Old bolt sheared? Over torqued? Bad luck?
 
Good question, take a look when you get in there, no bolt, it either dropped out or maybe not fitted? Put antisieze into the spline socket and on threads to do yourself a favour. ?I its sheared then you may need to use tools to get it out too? Also check cheese screw that goes into one of the torsion bars it should stop this from occuring. So it might be damaged?
 
As Adrian said, you've lost an M8 bolt which retains the ARB plate/wing to the trailing arm. It's easy to strip the thread in the trailing arm. It has nothing to do with the torsion bars. If you have stripped the thread, you can completely withdraw the ARB and drive safely. Let me know if so. I can easily tap it to M10. The bolt needs to be at least grade 8.8.
 
This is what you'll see when you clear away the rubber,
8mm bolt with 13mm head holds the teardrop (and brake bracket) to the trailing arm,
in centre of teardrop the dustcover plastic screw with 5mm allen head will likely be worn away.
With it being recently rebuilt I wonder if it didn't get any loctite and worked loose?


left_rear.jpg
 
Thanks for the replies. Here's a slightly better pic with the wheels off. It appears the m8 bolt has simply fallen out. So at a guess, installation error from the guy who built it.

Based on Peters reply I may just remove the ARB and drive it to the mechanics this afternoon as he's 1 kilometre down the road. thread_ok.jpgARB.jpg
 
PeterT said:
As Adrian said, you've lost an M8 bolt which retains the ARB plate/wing to the trailing arm. It's easy to strip the thread in the trailing arm. It has nothing to do with the torsion bars. If you have stripped the thread, you can completely withdraw the ARB and drive safely. Let me know if so. I can easily tap it to M10. The bolt needs to be at least grade 8.8.
Click to expand...
Thanks for the offer Peter. It looks like the thread is good. What length do I need for the m8 bolt? 25mm?

To cure some of my ignorance, is the ARB the beam going through the beam and the torsion bars are ones outside?

I have managed to push the ARB back in and felt like it engaged the splines, got it to line up nicely. Will still need a clean out but it should be ok for a very short drive?
 
Lined up
 

Attachments

  • Lined_up.jpg
    Lined_up.jpg
    685.7 KB · Views: 93
M8x20 will be long enough. You don't want a bolt, as it will have a shank. It needs to be a hex head machine screw or set screw, which have thread all the way to the head. Don't forget the spring washer.

ARB in the tube. Torsion bars are external.

If the holes line up and the wing sits flush against the beam, it's good to go.

243 Loctite is good insurance.
 
PeterT said:
M8x20 will be long enough. You don't want a bolt, as it will have a shank. It needs to be a hex head machine screw or set screw, which have thread all the way to the head. Don't forget the spring washer.

ARB in the tube. Torsion bars are external.

If the holes line up and the wing sits flush against the beam, it's good to go.

243 Loctite is good insurance.
Click to expand...
Thanks again. All bolted up. The rear ride height is a bit skewed side to side but I'll get that sorted. Really wish I had the time to learn this kind of stuff properly.
 
Yep, whilst this site is so helpful and really essential it can make one feel like an ignorant "D*****ead" at times. Glad you got it sorted though!
Well done all you pond paddlers who helped 'Lowpug'avert a really nasty situation. Knowledge is priceless isn't it?👍
 
Just realised I should have propped up the sagging arm with something so when I put it all back together it would be level. It'll have to wait.
 
DeeCee said:
Yep, whilst this site is so helpful and really essential it can make one feel like an ignorant "D*****ead" at times. Glad you got it sorted though!
Well done all you pond paddlers who helped 'Lowpug'avert a really nasty situation. Knowledge is priceless isn't it?👍
Click to expand...
It'll be very sad if AF goes away. At least we'll all still be d**kheads🤣
 
As you found its not hard to do so do your own thing!
 
This is all back together and working well. Back to silent and smooth suspension! New tyre fitted yesterday. Question though. The mechanic had a look through the whole rear end when checking and he thinks the right side splines on the ARB or the end plate are worn and thinks it could be the reason it pushed the left side off. Plausible theory? Either way he's keeping an eye out for a new part but says they are getting hard to find.

Certainly sound plausible to me as my old road (push) bike had gxp cranks that have splines either side. When they wear the crank arms get loose and can work their way off the splined axle.
 
You must log in or register to reply here.
Top