Well, after getting my electrical gremlins sorted I went out and qualified and raced well enough to win my class at Mid-Ohio on Sat but on the last few laps I developed a bad vibration from my left rear. I have a bit of grease exiting the hub and paining my new Fikses in a nice Jackson Pollock but other than that I can feel no play in the wheel bearing in the horizontal plane and a bit of play in the vertical caused by some play in my rear strut. The only other thing I can see is that there is some rotational play (backlash) on the drive axle - could my diff be packing up?

Any ideas on what to check?

Tristan

 

Sorry I missed you at Mid Ohio. I would start by looking at 2 things.

1) Pull the drive axle and tear it apart. The stock grease is no good in the axles for racing. What you are seeing is grease that has become too hot and liquified and is no longer effective. The liquid is comming out throught the vent hole in the stub axle. So, you need to take the joints apart, clean them and look to see if there is wear (probably). If there is no wear, buy some NEO grease from some place like HRP World and repack the CV and continue to run and thus it is not the source of your vibration.

2) When did you last replace the wheel bearings? We are getting about 1.5 years on the rears of the 964 Cups and have stopped using Rueville and have had issues with *** bearings manufacturered in 3rd world countries. What happens is that the hardness is not very deep, so eventually the bearing race will pit and cause the vibration you feel. A simple "wiggle the wheel" test will not determine if the bearing is bad or not because it is still tight.

Geoffrey

 

Geoffrey,

I saw you out there. You came flying past me out of the key hole during the sprint race. I was driving 611 (Grey 964). You have a beautiful car - congrats.

Thanks for the info. Are there any good instructions or tips for pulling the drive axle? My axles are pretty new (I think, since the stickers look new on them - the car is new to me, first race).

No idea on the wheel bearings - perhaps they have never been replaced. I should assume so. I have a spare set of hubs still mounted on training arms that I could use in the short term while I re-build the others with new bearings. How difficult is it to pull the hub and replace it?

Thanks for your input and advice.

Tristan

 

There is a good string on CV joints directly below your recent post. Great info and pics on that exact topic.

 

If I knew at the track, I could have changed your wheel bearing there as I had the tool and a spare bearing. So, changing the bearing isn't hard, and I'd simply recommend you change both rear bearings proactively on a racing car.

Even though the drive axles are new, if you are seeing liquid grease come out of them, they won't last long if you continue to run them.

These are unfortunate issues about racing a street car. You do have to proactively replace parts, and some stock parts (stock CV grease) just doesn't cut it for the abuse it gets put through.

 

Geoffrey,

That would have been very kind of you. Thanks. What tool do I need for the bearing replacement? And do you prefer the SKF bearings over the ***? I'll get some good grease ASAP in order to re-pack the DV joints.

Thanks again for the info.

Tristan

 

I've been using SKF when I can get them, but I'd use a *** if I had to. The key has been preventative replacement since the bearings are cheap and not hard to do. You need the SIR wheel bearing tool kit and lots of places sell them. You might check EBS Racing. The master kit is about $350 and it comes in handy at the track when you have to change one in a hurry.

 

Tristan: My axles started to show problems with getting too hot and the stock grease coming out in as short as 2 hours of track time. From now on I'll have them re-greased before even putting them on when new.

Geoffrey: One day I'll actually get the time to learn how to replace the wheel bearings, but until then, ignorance runs rampant ... In addition to the Sir Tools kit, don't you need an additional tool to press the bearing into the hub? I was thinking of having a spare hub with it already pressed in in my spares (I already have the Sir Tools kit). As you have center lock wheels, I assume you also carry the monster torque wrench that's required too ...

 

All you need is the SIR tool kit and some method of torquing the wheel nut to 490NM. You install the bearing into the trailing arm (rear) or hub (front) and then press the hub into the bearing.

 

Geoffrey,

Is this the grease you're talking about? http://www.hrpworld.com/index.cfm?fo...action=product

There's also some CV joint grease, too. http://www.hrpworld.com/index.cfm?fo...action=product

 

It is the CV specifc grease. The bearings are sealed and not greaseable.

 

Okay, thanks, Geoffrey.

 

Geoffrey,

Good info. I found a couple of kits (both hub and bearing pullers) for about $270. Not too bad really. Can you always get the bearing out without removing the hub or must you remove the hub as well? I guess you disconnect the CV and then pull the bearing?

 

The basic process is to:

1) Remove wheel
2) Remove drive axle
3) Remove brake caliper
4) remove rotor
5) remove hub
6) remove bearing
7) Remove bearing race from hub
8) Install bearing
9) install hub
10) install rotor
.
.
.

you get the idea.

 

Know of a good place to get it from? The best price that I saw was $429 for the master kit.

My method for proper torque? Put all of my 240 lbs on the end of an 18" breaker bar. Viola - 360 ft/lbs of torque.

BTW, would you PM me the number for BBS Motorsport?