Just back from the alignment shop... -5deg caster was the best they could do!

Colby · 04-22-2003, 12:36 PM

Ok...'84 Carrera never been in an accident. Lowered to Euro specs. Went to get it aligned today (I installed turbo tie rods and new bushings all the way around) and they said that the "strut is all the way back in the slot" yet caster was still only -5 degrees! This is WAY low. Any idea what would cause this???

Colby

Neilk · 04-22-2003, 12:57 PM

Colby,

Who did your alignment? A Porsche shop or tire store?

I am tempted to go to NTB for my alignment. They only charge $90 (instead of $200+). If I watch the guy while he does it and make it clear that he will be rewarded for getting it to my spec, I imagine that alignment should be ok?

Any opinions?

Colby · 04-22-2003, 01:03 PM

Unfortunately, Firestone. 3 alignments for $99. They said they'd do the 911 for this, so I jumped on it. Took em over 5 hours; they had no clue. I eventually demanded to be back there and tell them how to do it. The rears were what really confused them, the front are pretty much like other cars. He said the strut couldn't go further back; don't know how you can screw that part up...

Colby

Neilk · 04-22-2003, 01:29 PM

5 hours??? Did you check to mileage? ;-)

Before I let them touch my car, I am going to ask if they have someone who is at least familiar with 911 suspensions. Although, after taking apart my ENTIRE rear suspension, I think I could tell the guy what to do in order to get it aligned properly.

1fastredsc · 04-22-2003, 01:38 PM

That's really high guys, i had my 944 lowered in the rear to match the springs in the front along with an alignment and it cost me 120. Although it took a couple of days since my car was in line to wait, still, it points straighter than an arrow at 100mph without my hands on the wheel (just a test, i don't do this often)!

tight as a bull's ass · tight as a bull's ass's Garage

Here's my story on the matter:

My steering wheel was a bit loose on the corners and in the straightaways so I took it to the local Sears Auto Ctr. for an alignment.

They charged me $69.99 for the 4 wheel alignment (they took 1 hr). I dropped the car off and picked it up literally 1 hr later. The guy who did it said he had done alignments for over 20 YEARS! so I was like "cool"

I got the car back, the wheel was tighter, was tight on the corners and car ran fine on highway. Good improvement from before. Only drawback was, when the car is running in a straight line, the steering wheel is a couple of degrees to the right.....

I complainted about this to the manager and after 1/2 hr of arguing, they decided to give me a full refund.

well, the car feels much tighter now (cornering and on straights) and this is something I can live with.

Colby · 04-22-2003, 01:56 PM

LOL, that's what pissed me off so bad. First thing I said is "do you have anyone here familiar w/ older 911's". Their reply "oh yeah, we have this guy who's been doing Audi's and Porsches for years". Ok, works for me. I told them if they had any questions to ask me. I saw a group of 3 mechanics under my car scratching their heads and walked in and asked what the problem was. The eccentric bolts wouldn't budge. They didn't loosen the two rearmost bolts. . At that point, I stayed there and walked them through it. I couldn't believe how long it took...it was painful to stand there and witness such incompetence. The main wrench admitted to me he had never worked on one before.

OH! Then, about 3.5 hrs into it, the manager came to me and asked to talk to me for a minute about "additional labor charges". I went off! I told him I was told they knew how to work on these cars. It turns out they didnt. This is a 1.5 hr job if you know what you're doing. Furthermore, you learned how to work on these cars, on my clock. I am an attorney and my billable rate is $150/hr. So the way I see it, you have cost me $600 today. And you dare to ask for additional labor? Hehehe, he dropped it and apologized.

Colby

911pcars · 04-22-2003, 02:37 PM

"....and they said that the "strut is all the way back in the slot" yet caster was still only -5 degrees!"

And if they told you minus 5 degrees, then they don't know what the specs are. Caster should be at least +5 degrees. Negative caster will allow the front end to wander in a straight line. They probably knew but told you incorrectly; that is if they were referring to the front end when they told you this. There is no caster adjustment in the rear.

Find a shop that has done this (alignment) on a Pcar at least once. It's not that difficult.

Sherwood Lee
http://members.rennlist.org/911pcars

masraum · 04-22-2003, 02:47 PM

Tight, that's easy to fix. All that needs to be done is to adjust the tie rod on one side in and the other side out a tad. If you turn the same amount on both sides you will not alter the toe, but you will change the location of the wheel relative to the tires.

Colby · 04-22-2003, 02:47 PM

No, I saw the machine. It said -5 deg on front caster...

Colby

jluetjen · jluetjen's Garage

You might also want to check the rake on the car. It can affect the range of adjustment for caster. But not getting enough caster is hardly a fatal problem, it will just make your steering a little lighter as long as it is still negative. The important thing is that it is equal on both sides. If it is not equal, the car will pull and do other strange things.

911pcars · 04-22-2003, 04:52 PM

If it's -5 degrees (both sides?), then it's about 10 degrees out of spec. There's usually more adjustment room for positive caster than this. With the struts at a vertical position, the caster will be zero degrees.

Sherwood

Colby · 04-22-2003, 05:37 PM

Yes, according to their machine each side was -5 degrees. This seems very wrong to me, if not impossible. Is there enough adjustment range in there to go -10 degree from factory spec???

How do I check rake? Yes, the car is a little twitchy on the interstate...

Colby

911pcars · 04-22-2003, 07:11 PM

Picture a bicycle. Notice the angle of the front fork? That's positive caster. This provides straight line stability. Now reverse the handlebar 180 degrees. This angles the fork in a forward direction which is negative caster for easier turning at the expense of straight line stability. You should have enough adjustment room to go + and - 5 degrees. Some owners even enlarge the strut opening slightly to obtain even more caster adjustment (fore/aft) and/or camber adjustment (left/right space).

The caster setting is only related to vehicle rake in that caster should be adjusted after ride height is set. However, a one degree change in vehicle rake affects the caster angle by one degree, so set height first, then align. To measure, place an inclinometer or equivalent (about $10 from the hardware store) on the door sill for an approximate reading. According to many, the front of 911s should be slightly lower than the rear, but as mentioned, this has only a peripheral affect on front end alignment.

Hope this doesn't confuse,
Sherwood

jluetjen · jluetjen's Garage

Most RWD cars won't have negative caster for two reasons:
1) It will make the car wander and won't center the steering
2) It will result in camber loss when turning which aggrevates a condition that strut cars have in the first place.

The opposite is true if the car has positive caster:
1) The steering will self center since the contact patch is behind the pivot axis which tends to pull the wheels straight
2) As you turn the wheels, the outside wheel will gain up to 5 degrees of negative camber which helps the fact that MacPherson strut suspension don't gain much camber (and sometimes may lose it) when a car rolls in a corner.

Sherwood; I wouldn't dismiss the affect of rake since a 1 degree change in rake (a small change) can reduce caster by 20%. Of all of the suspension settings, I'm not convinced that most people could even feel the difference between 5 degrees caster and 6 degrees. BTW; between '69 and '70 Porsche moved the top mounting points for the front struts forward 40' (2/3 of a degree) to reduce the steering effort.

89911 · 04-23-2003, 07:21 AM

NTB, Sears, and Firestone for alignment on a 15 year old 911? And you are upset they didn't get it right? Get in touch with your local PCA chapter and get a few references. Sure some higher priced shops can also screw up the alignment, but checking with a shop that has satisfied clients has got to be better then trusting a kid that has worked at Sears for two months with a manual.

tobluforu · tobluforu's Garage

I have to admit that you have more balls than I. What I mean is that I would never trust a place like that.

Colby · 04-24-2003, 07:59 PM

Ok, lesson learned. Trying to save a few bucks has proven more than not worth it.

The 911 was handling funny and a clunking sound was coming from underneath the car today. Reached underneath and the sway bar was loose (Weltmeister..attaches to adjusting nut). Jacked up the car and THE IDIOT FORGOT TO TIGHTEN THE ADJUSTING NUTS!! All four were loose, one nut is now gone (I sure hope I can still order one). I am beyond pissed. I am going down there tomorrow, demanding a refund AND am keeping the coupons for 2 free alignments (for my Jeep at another Firestone shop). Uggh...I can't believe this!

Colby

RoninLB · 04-24-2003, 09:19 PM

Quote:

Originally posted by 911pcars

According to many, the front of 911s should be slightly lower than the rear, but as mentioned, this has only a peripheral affect on front end alignment.

Sherwood

I think the 1deg rake sets the center of gravity under the dash

masraum · 04-24-2003, 09:20 PM

I'd rather do it 4 times myself than have a shop like that do the work. The only reason that I have my other cars done by that type of shop (I probably shouldn't) is because there is generally less to adjust, they do them all of the time, and it seems less important for some reason. I guess that also explains why I always end up back twice and never think they really got it quite right in the end.