GT Lower Ctrl Arm

[ConreroGT]

After re-assymbleling my GT front suspension I noticed.....now that it was clean...my passenger side lower control arm is bent.

Can they be repaired or should it be replaced?

[ben]

lets see pics
bent bad or not

[namba209]

I guess it would depend on severity of the damage, Kyle. My old school alignment shop has a 20 ton press and I've seen the "old head" there tweak a suspension member on it to get it right. I guess it would depend on the metal composition, ie., if it is weak in the bend area and will it bend there again.

[ConreroGT]

I think I'll just look for a good used one.

No pics yet, but it's bent enough to were the bushing is no longer parallel to the bracket on the control arm. (Bolt-from-hell bracket) I would have to force the bushing in considerably to make it fit.

[baz]

kyle have a look for the changes rallybob does to his to stop them twisting , it might be a good idea if you get a spare set to have the old ones put right then welded up with the bracing in for the future as i think you will be twisting more in the future with spirited driving and your car

[Gordy]

I would think that since you would need to go thru the trouble of removing the control arm to straighten it that it would be wiser to just buy a good used and do it right. I wouldn't want a possibly weakened suspension part on the car. You see them on e-bay for $10 or someone on the site here will have one.

[GTJIM]

Opel front suspension components are very prone to bending - they are small and light compared to US domestic cars.
Once steel has been bent it has gone past what is known as its 'elastic limit' and is permanently weakened. Straighten it out and it will bend more easily next time as there has been permanent damage done to its crystal structure - especially since it was bent cold in the first place.
When the suspension arm was made the bending done to it were carefully calculated to increase the beam strength - subsequent bending is usually in different places ... and completely random.
Here, even welding on any suspension component is completely prohibited unless factory done.
Your suspension ...... your life!

[jeff denton]

How on earth did you bend it?? The lowers seem to be pretty tough, I haven't bent one yet and my car has been in some pretty good scrapes, enough to bend the upper pretty badly.
My right lower A arm is made out of two stock ones welded together in such a way that the camber comes out quite visibly exagerated. It was reinforced a bit, yes, but even in stock form it sure looks pretty sturdy to me. It's the upper that looks and proves to be quite twinky in my experience. Every tire and rim ever mounted on that corner has sustained some damage. That area just seems to catch hell. When my car develops a push as the right front tire wears down other drivers have learned to not be outside of me coming out of the turns...funny how the outside car loses every time

[ConreroGT]

I don't THINK I bent it. I havn't really driven the car that aggresive...yet. I DID notice some more issues with the suspension. I always thought the car was a bit unstable at speed. I'm sure a little of everything contributed: Badly worn bushings, bent LCA, AND the upper ball joints on the left and right were facing the same direction. i.e. one was set - camber and the other was + camber!? My question is, which way is NEGATIVE camber? I attached a pic from the passenger side UCA:

Is the upper balljoint cap supposed to be near A or closer to B to be neg. camber?

[GTJIM]

Originally Posted by ConreroGT Is the upper balljoint cap supposed to be near A or closer to B to be neg. camber?

Negative camber is when the top ball joint is "IN" at position 'a' on your picture.
It is entirely possible for one side to be IN and the other OUT to get the cambers as close to the same as possible ..... depends how much things are bent from side to side and how worn the suspension bushes are.
It is possible to slot the mounting holes to 'even things up' as Opel has a very crude just two position adjustment here - the cross member that everything is mounted to can be bent as well. Due mainly to P Os running into curbs or bouncing off Supermarket parking place dividers ..... loose bolts here and there, worn ball joints and/or deteriorated rubber bushes don't help a lot either!
BTW: even one of the NEW lower A-arms that I found was bent! The inner rubber bushes were not in line......

[ConreroGT]

Thanks Jim- I'll keep the info in mind.

I have driver side mocked into place, but here's how it's looking so far: (to make sure I remember where everything goes! )

[neuropel]

Nice Pic!
Where did you get the red boots for the tie rod ends? Matches the other bushings nicely.
Todd

[ConreroGT]

OGTS - Red boots on the steering arms and black for the U and LCA's.

[SpringGT]

According to the FSM, the GT's were all set in position A in your picture at the factory and they refer to this as the "smallest possible positive camber'. Rotating the upper ball joint to position B would add positive camber in an all or nothing mannner, although I'm not sure of exactly how much it adds.

[jeff denton]

Slotting the ball joint holes makes for lots of variable adjustment, somewhere is a photo of how RallyBob went a step further and added a little jacking bolt to simplify the adjustment.
I found my lower control arm inner mounting bolt holes on the crossmember to be quite sloppy, had been run loose. I beefed up this area and used bigger, grade 8 fine thread bolts.

[ConreroGT]

Originally Posted by SpringGT According to the FSM, the GT's were all set in position A in your picture at the factory and they refer to this as the "smallest possible positive camber'. Rotating the upper ball joint to position B would add positive camber in an all or nothing mannner, although I'm not sure of exactly how much it adds.

So if the FSM is true and it's already set to "neg" camber, why would Gil from OGTS tell us to rotate the upperball joint 180 to get negative camber?? (This advice is given in the instruction sheet that comes with the sport leaf spring)

??

[jeff denton]

The sport leaf makes the front ride lower, correct? So the A-arms think they are in "bump" when they are not, and when they really are in "bump" they are more so than ever. The camber angle is affected by this and needs to be adjusted.
Problem is, the adjustment method of just rotating the upper ball joint is kind of phony. Not much of an adjustment! Slotting this area of the upper A-arm fixes that.
This was probably never an issue with the average Joe GT. But to make one perform radically there are lots of things to overcome. As I was warned when I got the wild idea to race one... The front end has been extremely challenging, and most front end experts take one look and say "weird"...

[SpringGT]

The gt's have no negative camber setting. The initial factory setting (position A in your pictures) is a setting of 1 (+/- 1/2) degree positive camber. Rotating the ball joint flange makes the camber even more positive.So, position A is not negative in an absolute sense, merely closer to being negative than is position B.

As you know,this is not an especially good design since it only affords 2 adjustment choices, and this is why many Opelers have slotted the mounting holes for greater adjustability. I guess that the Opel designers thought that this was an adequate design tradeoff for an inexpensive, low-powered sports car. Who knew that we'd still be driving and demanding more from these cars 35+ years later.

The mantas however, had an initial factory setting of 1 (+/- 1/2) degrees negative camber and rotating their ball joint flange makes the camber even more negative.

As to why OGTS recommends rotating the flange,I can only speculate. The sport spring may alter the stock suspension geometry to where they have determined that this is necessary. Still seems like this would add positive camber to the GT and negative camber to the Manta.

[RallyBob]

While the GT front suspension has positive camber as delivered from the factory, lowering the car via OGTS' aftermarket spring will change the camber to negative. Rotating the upper ball joints after changing the front spring reduces the negative camber (more positive) a bit (it's still negative, just not as much), to improve tire wear characteristics.

[SpringGT]

Thanks! It seemed to me that lowering the front suspension would make the camber go negative, since it was so close anyway, but I haven't had a personal experience with the lowering spring.

[Dmcbrass]

I installed what OGTS calls the intermediate front spring on my 70 GT. As I understand it, this puts the front of the car lower than factory specs but higher than the sport spring. I left the camber at the factory setting and it was within factory specs when I had the car aligned. The car handles great and there has been no visible tire wear over the first 1000 miles.

[GTJIM]

My book shows: Camber, laden or unladen ............ - 0 degrees 15' to + 1 degree 45'
The whole thing is a balancing act to ensure that the inside tyre on a turn is loaded up to near vertical with the weight transfer.
More negative camber improves cornering but increases uneven tyre wear .....

[ConreroGT]

Done! Whew....

[neuropel]

Looks really nice!
Are those powder coated or painted?

[ConreroGT]

The whole thing was bead blasted and painted. I figured no one would see it anyway, why waste the money on powdercoating.