mackeyred96

Does anyone know what year and why GM went to the composite DOG BONES???????????

As some of you may know I had the upper composite pull apart last Sunday at E-town.

CFI-EFI

My parts book shows the same parts numbers, 1984 - 1988. 1989 and 1990 show different. Of course the parts book doesn't show what the difference is. 1984 - 1988 are definitely aluminum. My book doesn't go past 1990.

RACE ON!!!

xs650

Energy Suspension told me 1996. That was the reson they gave for not selling their poly bushings for 1996 dogbones. Take that with a grain of NaCl

I just checked my parts CD and 1988 through 1996 all list p/n 17999270 for the upper one. However, that doesn't mean they were the same when they came from the factory. That just means that 17999270 is the current replacement part.



[Modified by xs650, 5:28 PM 3/10/2004]

superlund

1996 was the first & last year for the composite rear control arms. I'd guess one reason for the change was to reduce manufacturing cost, and start testing durability for future composite suspension pieces on various GM models...

h rocks

John, the length of the bones is the same 88+. You can eliminate the problem by making up your own trailing arms with good heim joints and alum tubes that you can buy from any circle track parts house. (Coleman, Speedway, Behling etc. etc.) They will be light and strong. Just measure the bones from eye to eye, and get the appropriate length tube, joints and jam nuts. Get them close by eyeball, then just mate it up to the factory bone and insert a bolt in each end to get the correct length. The only thing you will need to either make or buy are some spacers for either side of the heims so that they "fill up" the space between the brackets. Or...you can just buy the whole kit from Exotic Muscle, Rippie or Guldstrand. Making it up is a LOT cheaper and just as effective.

mackeyred96

Great info guys, thanks :thumbs:

edsalinas

I wasn't aware that they did this? Can anyone post a pic of these things??

mackeyred96

I try to get MOJO to post my broken parts.

Mr Mojo

I'll try and stop by on Sunday and take some pics.

0ski_dwn_it

Mack/Mojo.

Is there any indication of what exactly caused the failure.

Get some real good closeups of the break marks and I will have the guys in our lab that are trained in crack propigation etc to take a look at it. They will be able to give an idea if it was load stresses that caused it or just simply a flaw in the dogbone itself that contributed to the failure. Not that its going to help you out in the end, but I think it would be interesting to see what they think.

Also wanted to mention that you should take a look and make sure your C-Beam is tight. If that was loose I could see that allowing some twisting of the rear. This would put the dog-bones in compression or tension depending on the side. This could possibly result in a longtime failure possibly.

Just glad mack it did not let go at high speeds. One of them hitting and diggin into the ground could be disasterous. :cry

Hope to maybe make it out there for an even next month... :cheers: Maybe I can drag Beach along for the long haul :cheers: