Tying up more bandwidth - Steering and brakes

Stuttgart951 · 02-03-2003, 07:41 AM

Thanks for all your help so far.

Im relatively sure Ill be taking the car to get inspected this week.

There are two issues that I briefly mentioned in my first thread (other than the backfiring)

Steering: Very heavy. It felt like the power steering was shut off. There was also "shimmy" in the wheel (but not the body) during the entire drive.

The roads we're even close to perfect - but I got the impression that perhaps the bushings were worn - or maybe the tie rods. In any event - there is 1/2 inch of "right left" play in the wheel with no effect on steering and the "shimmy" is not sensitive to speed. Matter of fact, the car itself rids perfect - the shimmy in the wheel doesnt effect handling at all. Tire presures were off in two wheels - but I dont think that would cause what I was feeling. Any problems areas that should be setting off the $$$ alarm here? New tires within 500 miles - "assumed" they are alligned and balanced.

Brakes:

Again - ALOT of effort required for miminal stopping power. I obviously wasnt thrashing the car - but I was very surprised the first time I tried to stop - took a whole lot of pedal effort. No brake squeel - no other noises. Didnt check for vacuum pull in pedal on startup. It felt like (as above with the sterring) the power brake system was shut off. Could this be a leaky master cyl or a vacuum leak?

How hard are these two problem to diagnose? I dont mind the work - I just want to know that I wont be replacing $10K worth of parts before I find a fix by accident.

I searched the BBS and tore through Wayne's book - but I didnt find the answers I was looking for.

Thanks again for the help (you guys should charge a membership fee - Ill pay it twice my first year.)

Rot 911 · 02-03-2003, 07:58 AM

Shimmy could be worn front end parts or unbalanced tires. Brakes? Now that is odd. Every 911 I have ever driven with powered or unpowered brakes had excellent braking modulation. My guess is possible collapsed rubber brake line, but it could be a number of things like loss of vacumn to the power brake servo. In any event none of the above is a major expense to fix. To me major is anything over $500-$600.

old_skul · 02-03-2003, 08:09 AM

911s don't have power steering, at least pre-964 911s. Why would you want that?

The brakes in 911s are very good, but require a lot more effort than other cars, I've noticed. There could be a problem with the vaccum booster, but this might actually just be normal operation and a perception issue.

The shimmy sounds like out-of-balance tires. There's little in the way of suspension problems that could cause that. Maybe a worn front wheel bearing.

The tie rod ends on a 911 are fairly good, but the 930 (turbo) versions are reputably better. That could explain the free play you found in the steering.

Stuttgart951 · 02-03-2003, 08:40 AM

No power - but the steering is boosted is it not?

Good to hear that none of the above would be a major fix - and I plan on doing most of the work myself (or at least learning how - hehe) so I can cut the cost down even farther - my concern, again, comes with the diagnosis.

Thank you for your responses.

Don Plumley · Don Plumley's Garage

The steering is 100% good old fashioned manual rack and pinion. Yes, mine is a bit of tug at low speeds, but well worth it for the precision it affords. I can barely sneeze when I drive - the steering input is quite precise. The slop you describe is the opposite of mine. FWIW, I have turbo tie rods.

I had a similar shimmy, but only over 60mph - and it was an un balanced tire.

Hard to tell about your brake question. They are certainly one of the very best features of my car - 1" to 1.5" of pedal movement, then steady pressure down halts the car. There is no feeling of "mush", but a very proportional input up to lock-up.

Interested in your PPI results. Hope you nail down a price before you get the estimate on the backfire, et al repairs.

Don

old_skul · 02-03-2003, 09:26 AM

The steering is not boosted in any way, no.

ZCAT3 · 02-03-2003, 09:40 AM

On the steering it could merely be bad tires or improper tire inflation (or tire balance, etc). When I pick up my recently acquired 87 the steering felt really sloppy at higher speeds. I was driving the car from Colorado to California so at the first service station I found I got out and checked tire pressure. It was way too high (set to about 993 specs). As soon as I adjusted it to the correct specs the steering felt as it should. Turbo tie rods (as noted) will eliminate any minimal slop that Carrera steering may have.

KTL · 02-03-2003, 09:54 AM

My steering was exactly as described. Lots of on-center play. Meaning, it had a BIG dead spot in the middle. I really noticed it after driving a friend's car that has the turbo tie rods.

New turbo tie rods and a relubed rack has the steering razor sharp again. HUGE difference. Both jobs are fairly simple do-it-yourself stuff.

I think the brake issue may be like the others said. You may not be used to the feel of the 911 brakes? They do require a bit more effort. One reason is because of the pedal arrangement. Being that they're bottom-hinged instead of top-hinged, you use your leg a little differently to push the pedal (at least I do).

Still, the brake issue should be thoroughly checked. The rubber lines and the vaccuum leak are simple checks. If the rubber hoses are original, they should be replaced as they're getting pretty old. For the vaccuum lines, you can start with the hoses at the vaccuum booster and then look at the hoses in the engine compartment on the driver's side front (firewall) location. These in the engine compartment tend to get loose over time.

From the other threads, the car sounds like a misfire more than a backfire. A backfire is usually an exhaust leak and occurs when the throttle is released. If the car is sitting at idle and stumbling, most likely sounds like the air meter, injector, or cyl. head temp. sensor issues that have been mentioned already? Hard to say. Could be a fouled or faulty spark plug too. Always check the simple stuff first!!!

old_skul · 02-03-2003, 10:28 AM

I concur with KTL. A backfire would be heard inside the car at any speed and you'd probably suck up seat leather with the pucker factor. A misfire is normal after part- to heavy-throttle driving when you lift off. Also, fouled plugs, O2 sensor, anything old and dirty in the engine can make it happen.