snapped pressed wishbone

[DamoM]

I was at the Audi day at castle combe on Saturday hammering round in my UR quattro when braking for the 1st chicane on the 4th session of the day and my right front wheel slammed into the back of the wheel arch and locked solid at 105 mph!!! Just about avoided a big one!

Anyway, turns out that the front wishbone had sheared off at the frontmost bush.

The thing is, because I use the car exclusively for trackdays the car has alloy wishbone bushes all round (along with alloy subframe mounts) and when I picked my car up from MRC on Thursday following a remap, when I drove the car out of the estate and went over a few bumps one of the rear wishbones sheared off at the front bush.

However, some investigation showed that the bush had seized on the wishbone so the wishbone had then just suffered metal fatigue. Therefore, Friday was spent putting on new rear wishbones, making sure that they were well greased and moved well. We then checked the front ones and decided to do the same to make sure that all was well.

The failure was therefore a real shock to me in more ways than one!

My car is running Corey's porsche brake system, trackday pads and super sticky trackday Yokos and so i am guessing that the combined stresss of all of this is just a little too much for the standard components.

I spoke to Kim Collins at the circuit and he recommended the cast wishbones from the late 20v URs.

Does anybody else have any opinions or experience of the way forward? I need to make sure that when I am leaning on the anchors at the top fo the hill at castle combe (on which I was hitting 135 mph - 5 mph faster than my RS4!) that my suspension is not going to fall off!

[stevieyid]

Hi mate i was right behind u when it happened. I saw a load of smoke and saw u on the run off bit. I was in the red UR, i did slow down to see if u was ok. We thought the engine had blown and it wasnt until the next lap we saw what had happened. Feel sorry for u mate hope u get it sorted

[DamoM]

Hi mate i was right behind u when it happened. I saw a load of smoke and saw u on the run off bit. I was in the red UR, i did slow down to see if u was ok. We thought the engine had blown and it wasnt until the next lap we saw what had happened. Feel sorry for u mate hope u get it sorted

Oh, yeah, I remember overtaking you i think it was before the corner before the 2nd chicane if you know where I mean?!

My brother (a non Audi man!) was driving my blue RS4 that was right on my tail and presumably followed through straight after me?!

It was a shame though as the car was running in the 1 minute 24s and the RS4 was only 0.5 second a lap quicker and that has full miltek and decatted pre cats so probably 400 bhp at worst!

Great day though!

[stevieyid]

Yeah i saw u going round the track previously so when i saw u in the mirror i thought better let this one passed my Standard 10v turbo is no match.

[caterpillar]

my wishbone snapped too, and few sek before i had about 100 miles/hour, but when it snapped i had only 5 miles( lucky me)
if the bush are seizing, it will happend!

[Fat Audi 80]

Repect to that UR mate. I watched you keeping a lot of powerful machinery very honest.

Sorry to hear about your mishap, we were down at quarry when it happened. Glad to hear it is nothing too serious and you can fix it.

P.S. I am sure most S2's run cast front wishbones from the factory, probably for that very reason...

Cheers,

Steve.

[DamoM]

Repect to that UR mate. I watched you keeping a lot of powerful machinery very honest.

Sorry to hear about your mishap, we were down at quarry when it happened. Glad to hear it is nothing too serious and you can fix it.

P.S. I am sure most S2's run cast front wishbones from the factory, probably for that very reason...

Cheers,

Steve.

Thanks! It was really good fun. The car has been a long while in the making and it has been quite a rewarding experience getting an old 10v to go that quickly.

Was hounding that convertible S6 that was on the QST stand and was all over it in the corners. The guy just wouldn't let me by 'with consent' and then just crept away from me on the straights. When we came in we went over to see it and the owner of the car was driving and he had a supercharger boltede on and had had it remapped at QST with a dyno plot of 495 bhp and over 500 nm torque! Knowing that I was surprised at how well the ur hung on on the straights!

I didn't know that the S2s came with cast front wishbones. Thanks for the info.

[volcano rs]

you could still use the steel ones if you have them seam welded

[diesel des]

Pictures of the failure points please

[WabTheKing]

aluminum next to steel is not the best plan due to oxidisation - and aluminium is certainly not a suitable material to make a wishbone bush out of, - not too bad as a subframe bush as nothing is rotating in it,

if i were you id be looking at replacing them with polyurathane or nylon bushes

or pressing an oillite bush into the centre of your aluminium wish bone bushes

who sold you aluminium wishbone bushes?

[DamoM]

you could still use the steel ones if you have them seam welded

Cool. Do you think that that would make them strong enough? I am anxious to know that when I stamp on the middle pedal that my wheel won't fall off!

[DamoM]

aluminum next to steel is not the best plan due to oxidisation - and aluminium is certainly not a suitable material to make a wishbone bush out of, - not too bad as a subframe bush as nothing is rotating in it,

if i were you id be looking at replacing them with polyurathane or nylon bushes

or pressing an oillite bush into the centre of your aluminium wish bone bushes

who sold you aluminium wishbone bushes?

I can't remember where I got them. It was through someone selling them on a forum. Will have a look and see. Thing is, the wishbone didn't shear right at the bish, it was about an inch outwards so I doubt that oxidisation was the issue. My subframe bushes are ally too.

I agree with you though about the unsuitability but I think it is more to do with lack of fore-aft movement putting stress into the wishbone and ultimately resulting in fatigue. I have already got my guys to get some cast wishbones (I want to get new ones for piece of mind) and I have some poly bushes for another project which I am going to get pressed in instead.

[DamoM]

Pictures of the failure points please

Will post one this afternoon.

[WabTheKing]

find out who you bought them off and tell them stick em where monkeys put there nuts

[mcandmar]

I would'nt use alloy a-arm bushings, never mind with alloy subframe mounts. You need some give in the suspension and in your case its seems the a-arms are now the weak link.

If its of any use i have one cast a-arm that i think fits a ur-quattro. Its not an S2/RS2 item so it must be off a UR. I think its the drivers side, if you want it your welcome to it.

Regards,

Mark.