Front suspension issue/question

[schiarchianis]

Hi all,

Here's the backstory: my car ('78 SC) was in the shop for some engine work a couple of months ago and while returning from a test drive, the mechanic heard a "clunk" as he drove up the curb and into the shop. Upon inspection, he discovered that the torsion bar cap (#15 in the PET picture) on the left/drivers side A-arm had come off, and that the torsion bar had actually backed out of the front torsion bar "reverse lever" (#19). He got it all put back together, but when I got the car home, I noticed two things: 1. the front suspension was higher, by about 1.25 inches, than what it was before that issue happened, and 2. the orientation of the left reverse levers was not the same as the right. The car drove fine while I was on my way home from the shop, although I think the toe values are a bit off now that the front end is much higher than before. Rather than take it back to the shop, I'd like to orient the left reverse lever myself, so that it matches the right side, and then I'd like to lower the front of the car back to where it was. What would be the order of operation to accomplish this, and are there any gotcha's I need to know about? Is it as simple as loosening the adjusting screw, removing the left reverse lever, then re-installing so it matches the right side? I'm hoping so, but something tells me it's not. Thanks in advance for your feedback...Steve

[TJJSC]

Hi,

It seems strange to me that the torsion bar or lever cap came loose as theoretically this can't happen as long as the adjusting screw is in place (it's blocked by the aluminium suspension crossmember).
So it might be good to investigate how this could have happened.. ?

The difference you now see is probably caused by the torsion bar or the lever cap gotten reindexed after reinstalling. Mind you, the left and right lever cap angles are not necessarily exactly the same, they just set the pre-tension on your torsion bar affecting the ride height. So as long as you can set the correct ride height (left and right) there's no need to reindex.

Reindexing in done by (with the front of the car raised/wheels off the ground) taking the cap (after removing the adjustment bolt) of and replace under a different angle and/or take the torsion bar partially out and place it back under a different angle. As the torsion bar has 2 different sides you can make smaller steps by doing both in a different direction. This can be a bit of a trail and error process.

Ther'se lots of info on this to be found on internet / P911 101's or in the typical workshop manuals. Hope this helps a little.

[schiarchianis]

Thanks for the good info TJ. What my mechanic thinks is whoever was in there before had removed the torsion bar adjuster cap in order to remove and inspect the torsion bar. Upon reinstallation, he thinks maybe the adjuster cap didn't fully engage on the torsion bar splines. When he drove it up the curb back into the shop, the torsion bar backed itself out of the adjuster cap somehow. So the adjuster cap remained in place the whole time. At least that's how he explained it to me. As the car sits now, the fender lip on both sides is 26 1/4 inches from the ground, and I'd like to get it down to 25 1/8 inches. So I'm just not sure of the steps to take in order to make that happen.

[PopsRacer]

you just turn that adjuster screw to raise or lower the front. Go slow, each side affects the other. But you can do it with the car resting on the ground, there is enough clearance.

[PeteKz]

Corner balance the car after you mess with the front T-bar adjustments. If the car pulls to one side or the other, your corner balance is off.

[schiarchianis]

Thanks guys, although I've never lowered the front end, I'm confident I can do it. I just wasn't sure if I needed to first, position the drivers side adjuster so it matches the passenger side, and then commence the lowering process. I've been under that car dozens of times, and the position of the adjusters always matched side-to-side. Also, if I want to lower the front 1 1/8 inch, approximately how many turns of the screw would that be?

[ccallana]

Originally Posted by PeteKz

Corner balance the car after you mess with the front T-bar adjustments. If the car pulls to one side or the other, your corner balance is off.

Not just corner balance - Toe will be messed up as well. will need to fix that

[PeteKz]

Be cautious about lowering below the minimum specification (measured the Porsche way). That changes the geometry of the MacPherson strut and adversely affects handling. If you want to go lower, start thinking about struts with raised spindles and bump steer correction.

[brighton911]

"Upon reinstallation, he thinks maybe the adjuster cap didn't fully engage on the torsion bar splines. When he drove it up the curb back into the shop, the torsion bar backed itself out of the adjuster cap somehow. So the adjuster cap remained in place the whole time."


The mechanic's statement about the cap not being fully engaged to the splines does not wash with me. In order for the adjuster bolt to fit through the hole, the cap must be fully home on the torsion bar. Put another way, unless the bolt actually fell out, there is no way the adjuster cap can back off the torsion bar. IMO, you might want to find another mechanic

[schiarchianis]

Originally Posted by PeteKz

Be cautious about lowering below the minimum specification (measured the Porsche way). That changes the geometry of the MacPherson strut and adversely affects handling. If you want to go lower, start thinking about struts with raised spindles and bump steer correction.

I totally get that. I've had the car 4 years, and it was at RoW ride height when I bought it. I really liked it there, it handled and drove nicely. About a year ago I took it to a shop to have all new OEM rubber bushings installed, front and rear, plus new Bilsteins. When I picked it up a week later, the mechanic at that shop had lowered it to slightly below RoW. It looked cool, but I didn't like the way it handled. When I took it in for the alignment, they couldn't get it aligned to spec. as it was a bit too low. I told myself I'd live with it for a while, then have it raised up again to RoW. The car isn't running yet; I had Tony rebuild my WUR and FD, and they should be delivered to me today sometime. Once I get those installed, I'm gonna have it raised up to RoW ride height. Plus an alignment and corner balance.

[schiarchianis]

Originally Posted by brighton911

"Upon reinstallation, he thinks maybe the adjuster cap didn't fully engage on the torsion bar splines. When he drove it up the curb back into the shop, the torsion bar backed itself out of the adjuster cap somehow. So the adjuster cap remained in place the whole time."


The mechanic's statement about the cap not being fully engaged to the splines does not wash with me. In order for the adjuster bolt to fit through the hole, the cap must be fully home on the torsion bar. Put another way, unless the bolt actually fell out, there is no way the adjuster cap can back off the torsion bar. IMO, you might want to find another mechanic

Thanks for the input. I agree 100%. In fact, I was out in the garage last night measuring the ride height. I noticed the left front tire had some very shallow cut marks where the tread meets the sidewall. I looked up at the fender lip and noticed a two inch section was bent down. So it appears to me that the suspension collapsed somehow and the tire made contact with the fender lip. The way the mechanic explained to me was he thinks the last guy to install that torsion bar pushed it too far to the front of the tube, and when the adjuster cap was installed, it wasn't fully engaged on the splines of the cap. I'm no expert, but I would think that once the torsion bar is fully seated in the front splines, that it would also be completely seated in the rear, once the adjuster cap is installed. Anyway, I'm definitely going to dig deeper and try and get more answers.

[nickelplated5s]

It's possible you have a broken T Bar. FWIW my car is lower than yours and handles straight. Post your suspension rebuild setup. I just ordered the rest for my rear yesterday.

[schiarchianis]

Originally Posted by nickelplated5s

It's possible you have a broken T Bar. FWIW my car is lower than yours and handles straight. Post your suspension rebuild setup. I just ordered the rest for my rear yesterday.

I went with all stock rubber bushings from Elephant Racing, including the front and rear swaybar bushings, plus four new Bilsteins. I asked for the mechanic to inspect all four torsion bars. He left the original fronts, but replaced the rears with 26mm solid Sway Aways.