924Board.org

[cellsitedude]

Hey there,
Since I am new to the Porsche 924 I have some questions that many of you may with more experience may be able to answer.

I have only been able to drive my 79 924 NA around the neighborhood since I got it.
And I took it up to the body shop last week and had it out for the first time on the highway.
I really liked the way it handled and how well the engine ran.
But at speed I had some noises that I was unsure about and unable to visualize what may be the cause.
All the sounds were what seemed to be coming from the rear of the car.
The main one I thought could be a bad shock or mount but it had a thump to it that I could not duplicate as I went over bumps. And then there was a low frequency drone sound (the best I can describe) when I was coasting and not under load or deceleration that also seemed to be coming from the back end that I could hear in the trunk area.
I did not sense any major vibration that would lead me to think it could be a U-joint or CV joint and don't think it was the differential, but I am still a bit unfamiliar with my car as I have only owned it for a month and have not had it on the road yet and is still in the restoration phase.

My question is:
What kind of suspension/drive train components on the 79 924 5-speed are common to wear out and should be put on my winter list of parts to buy?
Also, What kind of things should I look for and look at to restore my car to near new ride quality and quietness?

Any ideas or advice or what to look out for would be greatly appreciated.

Thanks

WN

[Ozzie]

Well you can start with the pinion bearing in the flywheel, torque tube bearings, CV joints, rear wheel bearings and rear shocks and out of balance wheels.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[Rasta Monsta]

How many miles on the car? I would sure start with a CV teardown, and change your gear oil as well. Both are cheap and critical procedures.

You may also check all your exhaust mounts while you are under there, and replace any that are MIA.

Good luck, and welcome to the Board.


rasta
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[cellsitedude]

Thanks,
Those sound like some really great places for me to start.
I know the exhaust mount is good because I replaced it myself.

I don't know exactly how many miles are on the car but the odo stopped working at 85,000 so I am sure it would be wise to start purchasing CV and other drive train parts for replacement.

Someone mentioned the pinion bearing in the flywheel. I am unfamiliar with this but I will have to open my repair manuals and check this out. It sounds like a difficult part to get to and replace. And how about the torque tube? Will that require the removal of the trans to access?
Is there a U-joint or CV connection from the shaft of the torque tube that could cause noise during coast? if so.. how does one go about troubleshooting without major disassembly or trans removal? Any tricks you guys have come across?
I will take a close look into my manuals, thanks for the suggestions and advice!

WN

[Smoothie]

Pinion bearing in the flywheel?..we normally call that a pilot bearing 'round these parts. If it's making noise, it'll make more of it while the engine's running, but you're stationary, or while coasting with the clutch pedal depressed (in other words, any time the engine and driveshaft are not spinning at the same speed).

There are 4 CV joints at the rear - one at each side of the gearbox, and one at each rear wheel. They're roughly $100 each new. If this hasn't been done already, they and the halfshafts they're attached to can be flipped -or- swapped to get more miles out of them. A search for all terms flip swap by author "Smoothie" should find you some info on it. You'd also clean and regrease them (and use the correct high pressure lube) while you're at it..
Worn cv joints normally make more of a rythmic knocking or clunking sound. A "low frequency drone" may just be a normal transmission sound, but I notice it more on easy accelleration with my car, and less while coasting. The amount of sound insulation and carpeting that you have in the luggage area greatly affects the gearbox noise level - as does the type of gear lube.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[gohim]

If your car only had 85K miles, on it, the parts that have been mentioned most probably are not worn-out yet. But most probably it has many more miles on it than 85K, and the car needs some simple maintenance that many 924 and 944 owners ignore, because it's so messy.

I would start by checking the passenger compartment (particularly the spare tire area, and the saddle bags (pockets below the carpet behind the rear wheels) for loose junk rattling around (tool kit or loose tire hold down?). The cv joints and the rear wheel bearing are probably still good, but by now, the original lubricating grease is history, especially the grease on the left side cv joints and wheel bearings since they get cooked by the exhaust system. The rear axle nuts must be removed to service the axles. They are installed with 250ftlbs or more of torque. The easiest way to loosen them is with an impact wrench. Air powered ones are stronger, although a good quality electrical impact wrench may be strong enough. You will need at least two-three containers of a high quality grease to repack both the front and rear wheel bearings, and the cv joints. I use Valvoline Full Synthetic myself. It can be hard to find since it costs more money (about $5 a tub/tube for Durablend 50% Synthetic or $6 a tub/tube for 100% Synthetic), but it doesn't breakdown and/or run off.

The original front struts and rear shocks are probably soft by now. The rubber mount on the top of the front wheel struts have probably collapsed down, and the metal parts of the upper mounts are probably rubbing on the upper spring perches. This results in increased steering effort, and knocking noises when you go over bumps. When the rear shocks need replacement you will hear some clunking over bumps.

I suggest buying new shocks and strut inserts, and not the cheapest ones (NO Monroes, Gabriels, or low line KYBs). I actually prefer Bilstein Sports or Koni Sports on my street cars. The replacement rubber upper front strut mounts are 944 pieces, and only cost around $30 each. When you reassemble the front struts, install the 6mm spacers that Porsche recommends between the upper spring perches, and the upper strut mounts. This is help prevent the grinding next time the upper strut mounts collapse.

[Min]

May want to try removing the sound deadening pad from the hatch area to see if it makes it any easier to identify the noises your hearing. Its possible its just regular transmission noise. Personally, I'd be disassembling everything in the rear and replacing or repacking it all and replacing anything that looks worn out (cv boots, grease seals) Which I'd be doing if I was you even if there was no noise (preventive maintence is the best kind).

Min
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Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting.