924Board.org

Tiny · Joined: 10 Apr 2006 Posts: 502 Location: London, UK

Hey Guys,

When I was adjusting the rear brakes on my 924 I heard a dirty grinding noise from the inner CV area... while spinning the rear wheel in neutral.

I turned and saw this. pg 230 in the haynes.... Sounds and looks like the grease has leaked out of the cv joint on the inner end of the rear axle. Is my guess right?

I just wanted a bit of advice as to what the problem is here, and what parts I would need to buy...and the best way to go about fixing it?

I haven't replaced the rear wheel bearings yet, but they're not making any noise, yet.

Thanks eveyone for your ongoing help!

Tiny
_________________
*****1981 - 924 - Auto - London, UK******

morghen · Joined: 21 Jan 2005 Posts: 9069 Location: Romania

that could be oil and dirt. check the oil level in the gearbox...you might have a bad seal.
_________________
Supercharger and EFI kits
https://www.the924.com

Tiny · Joined: 10 Apr 2006 Posts: 502 Location: London, UK

I see,

Checking the haynes, it looks like it could be the rear axle flange seal that needs replacing. Page 167

I have not yet checked the diff oil level. Better get the 17mm hex bit and do that as described on page 179.

ATF oil level is checked and fine.

It sounds like I have worn something out though, when I spin the wheel in neutral. oops.

Tiny
_________________
*****1981 - 924 - Auto - London, UK******

emoore924 · Joined: 13 Apr 2004 Posts: 2815

Doesn't look like CV to me. A torn boot would fling grease up onto the underside of the floor there, not oozing out off to the tranny side of the CV. You might have a couple of problems if you're reporting grinding too...

!tom · Posted: Tue May 20, 2008 2:57 pm Post subject:

Check the driveshaft for rubbing against the exhaust when the suspension is fully extended.
_________________
78 924 NA
5-lug

Tiny · Joined: 10 Apr 2006 Posts: 502 Location: London, UK

It's not the exhaust rubbing, as that runs down the othe side of the car.

The grinding sound only comes from the leaky area when I spin that side tyre by hand. I can feel friction too.

However, the passenger side wheel spins smoothly/freely in neutral. No grinding noise.

I'm really hoping it's not something in the transanxle which is worn out, as that looks like a complicated little box of tricks!

Tiny
_________________
*****1981 - 924 - Auto - London, UK******

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Looks to me like there may be two problems.

#1 cv joint may be bad. Look at the angle. It doesn't look like the axle is lined up with the joint (running to the center of the joint), plus there is serious rust going on in there, when there should be rust if the grease is good.

#2 as someone else already mentioned, all the lost lubricant appears to be at the bottom, as if it's an oil leak, not a grease leak which would be splattered 360 degrees as the joint rotates.

Rich H · Posted: Tue May 20, 2008 5:38 pm Post subject:

Worst case its diff output shaft bearing...

Check that diff oil level ASAP!
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

Tiny · Joined: 10 Apr 2006 Posts: 502 Location: London, UK

Thanks guys,

Oh, the reason why the axle isn't lined up is becasue I have raised the rear of the car from below the gearbox in that pic. you can just about see the block of wood at the very bottom of the photo.

The splattering is definitely 360º ...all the-way-around the axle joint. Unfortunately, the flash went off and photo doesn't show it properly.

It's overalls o'clock
_________________
*****1981 - 924 - Auto - London, UK******

Tiny · Joined: 10 Apr 2006 Posts: 502 Location: London, UK

...having a great time trying to locate the diff oil fill/drain plugs.
haynes says left side of diff behind the axle flange....ozzie...help!
= ] 10.30am....too early for a beer? heheh
Tiny
_________________
*****1981 - 924 - Auto - London, UK******

morghen · Joined: 21 Jan 2005 Posts: 9069 Location: Romania

you might have a shot seal and dirt getting in. or you might have a bad seal and a bad bearing. Clean the area first, unmount the CV and take a look around...you will probably see where the geasy stuff comes from.
_________________
Supercharger and EFI kits
https://www.the924.com

924RACR · Posted: Tue May 20, 2008 10:13 pm Post subject:

Right, I'd be concerned about the seal and the condition of the bearing. If only the seal needs replacing, that's no big deal, and you should be able to replace the seal itself (which shouldn't be all that expensive) just by removing the CV, then the drive flange (one allen-head bolt in the center, 6mm IIRC), then pry it off and drive in a new one.

To check condition of the bearing, after you remove the CV check to see if there's radial play in the bearing.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Tiny · Joined: 10 Apr 2006 Posts: 502 Location: London, UK

sweet, thanks vaughan and morghen

i just cleaned up the area, and found those 8mm triple square bolt heads holding the half shafts. local auto supplies place only stocks the torx heads. typical! ....so will have to mail order that bit.

I noticed this time...as i raised the car from the trailing arms is that the grinding noise is gone. The axle has remained in its normal horizontal position...as opposed to before...I initially had raised the car from below the diff...so the arms were lowered and drums were hanging on the cv joints.

anyway, thanks for the good advice guys...ill get ordering seals and that triple square bit
tiny
_________________
*****1981 - 924 - Auto - London, UK******

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Not sure if these guys ship to the UK, but here is an excellent, affordably priced set of triple-square bits:

Also, this thread is a bit tangential to your repair but might be worth a read.
_________________
erstwhile owner of just about every 924 variant ever made

morghen · Joined: 21 Jan 2005 Posts: 9069 Location: Romania

you should also check the CV condition under that rubber boot, add some CV grease and if necesary rebuild or replace the CV, the noise means that the CV is worn or maby damaged. So check and replace the grease inside the rubber.

i would not recomend jacking the car by the drivetrain or the arms....just use what the factory provided.
_________________
Supercharger and EFI kits
https://www.the924.com