911 Front ride height adjustment

JackS · 05-20-2003, 05:03 AM

I would like to hear the final opinion on ride height adjustment for mid year 911's. The ride height on the front of my 74 is about 1/2 inch too high. If I turn the adjustment bolt counter clockwise two complete turns, will that give me 1/2 inch lower ride height?
Will that affect toe enough to require an alignment, or will I be OK with a half inch adjustment? Thanks for the usual good advise guys.

IROC · IROC's Garage

I don't know about the "two complete turns", but you should be able to lower the car a half an inch without problems. As for the alignment, it probably depends a little on where you're at right now, but I'd try it and see how it turns out. You can "eyeball" toe and camber well enough to see if anything is greatly out of whack. If in doubt, take it to NTB or some other alignment shop - usually they will check your alignment for free.

Mike

n8marx · n8marx's Garage

I have fiddled with my front suspension quite a bit. On mine 1 complete turn gives 1/4 inch of height change. I assume it'd be the same for a '74.

masraum · 05-20-2003, 07:38 AM

Just as a note, I had NTB check my alignment once just to see what it was set to, according to thier print out the alignment was all over the place, but it tracks straight at 100 and handles well. I have checked the alignment using the tried and true DIY methods and they couldn't even CHECK the alignment right much less set it. As a matter of fact, I have been for a few years getting my tires there (my other cars), so I occasionally have them do the alignment too. Everytime I get a car back it pulls and/or the steering wheel is off. I always have to take it back at least once, and half of the time the numbers on the print out they give me are off. Thier reason is always "that way the crowning in the road isn't a problem."

KTL · 05-20-2003, 09:29 AM

I agree that one full turn of the adjuster bolt drops the car approx. 1/4"

Funny thing that IROC mentions "eyeballing." I think I need my eyes checked. When I did my turbo tie rods, I put the new rods next to the old, original Carrera rods and got them close by eye- not easy to do. Drove around on some old crappy tires for a while and they wore out pretty quick. Just had the car aligned last week and it turns out my eyeballing of the tie rods had my toe-in at approx. 8 deg.!!!!! No wonder the thing tracked so straight!

Anybody with good alignment knowledge (not me BTW) should not give you back a car with an off-center steering wheel. The same amount of turns to each tie rod in the necessary direction will center the wheel.

The number of turns center-to-lock in each direction will not be exactly the same, but this does not really matter in a street car. As long as the amount off-center is not a huge amount, the equal turn to each tie rod method should be just fine (too much adjustment may cause binding). To do it right, you should center the steering rack, set your toe, reinstall the steering wheel, and then make the necessary adjustments to center the wheel if need be.

Gunter · Gunter's Garage

For an SC, I find 25 inches to the fender lip front, and 24.5 inches rear about right to get the one degree nose-down attitude. With the spacers under the rack, the bump steer is kept to a minimum at that setting. When you say that the front is too high, what is the height? Do you have spacers under the rack?

JackS · 05-20-2003, 10:04 AM

Thanks for the input from everyone. My rear ride height, measuring from floor to fender lip is 24.5 and the front is 26.5. It does not look as bad as one would think. I think I'm going to give it a go. Should I take the load off the whhels while adjusting?
Maybe I'll try to bring it down 1/2 inch and see. You can check what it looks like here. Thanks again.
http://members.tripod.com/radiology_residency/index.htm

Jdub · 05-20-2003, 10:18 AM

Yes, I'd think you'd want to pull some weight off the front end and then turn the bolt.

One question if I may to the group: When new tbars etc. are put in, do folks put slight weight on the tire and *then* put the cap to the tbar end so that you will have full adjustment range? That is, do you set the wheel in relation to the car prior to capping, or do you put the cap on the tbar with the car in the air? I'd think that, unloaded, the suspension would not be close to where it needs to be and you'd be recapping the tbar later on.

John

masraum · 05-20-2003, 10:29 AM

26"/24.5" is too much difference. You really should get them closer together with preferably only .5" difference (higher in the front).

Gunter · Gunter's Garage

JackS: I agree with Steve, If your front is 26.5, you would have to come down more than 1/2 inch. If you go for 25inches, there will be bump steer unless you install spacers under the rack (easy to do) Jdub: I installed the cap by guessing the position, then came down on the jack, pressed down on the shocks, let it sit and when more adjustment was needed, I just jacked up again and indexed the cap by one spline.

KTL · 05-20-2003, 10:41 AM

You dont have to unload the suspension to adjust the front. A regular length socket wrench provides plenty of leverage for lowering. And you don't have to push hard at all when lowering. Raising, you have to push a bit harder.

Since you know how much you want to lower it and you need to lower it a good bit, i'd unload it. Too much turning on the crossmember might wear on its surface. But, if I do remember correctly, the place where the adjuster bolts bear has a hardened piece of metal inserted at this location just for this reason????

John,

You're correct in saying that you need to raise the A-arm before you cap it with the t-bar cap. If you don't raise the A-arm the car will sit quite high when you set it back on the ground.

What I did is I measured the height from the floor to the center of the wheel cap (call this "A") which is always the same distance. The height you want to set the car at is the 25 in. height that Gunter said, which is from the floor to the fender lip (call this "B"), with the car on the ground. B minus A = C = wheel center to fender lip

With heavier bars (I installed a 22mm front bar), I assumed the susp. would not travel as much when loaded. So, when I installed the bar, I set my "C" measurement about 1 inch lower than what I measured with the car on the ground. Worked out pretty well. You'll want to install the cap so that it's centered in its range of adjustment.

Hope that makes sense?

Jdub · 05-20-2003, 01:35 PM

Kevin and Gunter:

Perfect - makes complete sense!

John

IROC · IROC's Garage

OK, I admit - I actually had to help NTB align my car the last time I was in there. I had done it myself, but had just done a major ride-height adjustment and was headed to the track that weekend and didn't feel like fiddling with it. Between me and the alignment guy, we did OK.

As for eyeballing, my eyes are calibrated to within 30 arc-seconds, so I routinely walk through parking lots looking at cars and shouting out camber numbers. :>) Actually, I was really referring to *gross* alignment checks. Like when I installed my rear torsion bars and had the spring plate so out-of-whack that I actually had positive camber in the rear...

Mike