Use of CV joints with grease cap.

[Gary71]

I'm going to drop my driveshafts off at Davemac on Monday to have new joints fitted but before I do has anyone replaced the CV joints with equivalents that have grease caps?

I'm fed up of those silly little gaskets that never work anyway and just create mess. The joints are available (108mm OD, 40mm thickness, 28 spline) but I'm not sure if there is enough clearance for the caps inside the gearbox output shafts or the stub axles.

My car has a 915 box and '75 ali arms with matching half shafts.

I don't want to buy the wrong joints as the joints with end caps won't have the groove machined in for the gasket so there's no going back.

Any advice will be appreciated.
Cheers
Gary

[911hillclimber]

If you can sort this you will do us all a service Gary.
Those gaskets are really irritating and very delicate while fighting it out under there.

Personally, my guess is there is room for the caps, but I do not actually know.

[Uk911]

I've just had my shafts and cv's done at dave macs great job and mike bainbridge gave me the part number for the Porsche plastic caps that go on the gearbox end cv so you can undo shaft without getting covered in grease, if that's what you mean I post the part number in the morning I'm at work at the moment and the plastic caps are at home, they were about £7 each and in stock......Mark

[Gary71]

That would be great. I was thinking of the CVs that have the cap (steel) built in so you can still torque the joint up properly.

I'd be interested to see what the Porsche part is though.

[911hillclimber]

I think the 3.2/915 boxes have the dimension for the steel capped CV's, smaller than our generation of 915's.

I've had to do double periods of washing-up to get CV grease out of my skin...

[Uk911]

Porosche part is 99733226700 called closure cap drive shaft and is made from steel and fitted prior to fitting cv to gearbox flange and tightening up......hope that helps...mark

[fetuhoe]

Interesting subject.

I am not sure about which 108mm CV joint you are talking about but I thought that the early 4 bolt joint had been discontinued and that the only joint currently available was the 6 bolt joints used on the later 911s and 928.

If you are using 4 bolt joints do you know where they are manufactured? or do you just fit four bolts to the 6 bolt joint and not use the dowels?

GKN make 108mm joints in both 32mm and 40mm thickness.

There are a couple of issues with regard to the metal caps.

The cap only deals with joints that have a standard amount of plunge and as the 928 and other cars fitted with drive shafts with steel end caps are 32mm thick I believe they have less plunge than a 40mm joint. It is possible that if the 40mm joint does have more plunge there could be a problem but I don't have a definitive answer.

There is an issue with the flanges at both the transmission and trailing arm ends of the shafts is concerned with the space available and the cut out for the gasket.

If your flanges have the gasket cut out the commonly stated opinion is that they will be incompatible with the metal cap.

The clearance dimples in the cap don't clear the mating shapes in the flange although you may be able to modify this with a die grinder - it will still be a significant amount of work.

I would also worry about the cut out affecting the may in which the joint clamps when tightened against the steel plate as it won't be as well supported as when used with the flat flange that accompanies the shaft with the metal end cap.

[Gary71]

Morning, My joints are 6 bolt (replaced about 10 years ago) but I used the original 4 bolt CV boot flanges and fitted the dowels in place of the extra bolts with a small spacer inside the hole to stop the dowel being pushed in too far. The original joints (4 bolt) were also 40mm thick so I'm happy in terms of compatibility with the length of the shaft/amount of plunge.

The cut out for the gasket is on the outside edge of the CV joint rather than on the flanges, the flanges are flat (both ends) so could take the cap in terms of the mating face and joint strength, but the concern about clearance inside the flanges is the one I wanted to check on.

I'll probably remove a gearbox flange as it's easy enough and take it with me to check clearances, I'm not taking the wheel side out as I'll trash the bearing doing so.

The other option of course is to buy the joints with the gasket cutout and 4 end caps separately and see if they fit when I get home. Seems like a plan!

[Gary71]

SO...

Grease caps won't fit, not even close so you can forget that idea...

The joints with the groove machined in for the gasket weren't (aren't?) available...

So the recommendation is using a standard joint with a smear of silicone to make a grease tight joint. My concern will be torque relaxation but it's standard practive on these joints without caps evidently so this is the route I'm going.

I also took the oppotunity to try this cross grooved version to save some weight (amount TBA as I haven't measured them yet)



I'm getting my 4 bolt boot holders replated and then I'll put them back together.

Not the answer I really wanted, but I have tried!

[Brewster]

Could anyone tell me what they've roughly paid for a Dave mac service on a driveshaft? I have one clunking and two split boots since I've got the car running again. I'm tempted to take both off and send them to him. I called him and he wasn't willing to give even a ballpark figure at all without seeing them. If it's £300 for a pair that's fine. £3000, not so much.

[fetuhoe]

GKN Motorsport make a lightweight Joint 40mm thick which is part number MSN014.

It has +/-14mm plunge and there is a GKN Steel Cap which is compatible with this joint.

If you have solid flanges then these joints/caps should work.

There are many different types of 108mm joint available from the USA from EMPI and many other Off Road Buggy specialists some have very high quality 300M cages and spiders.

Re-building CVs and inspecting for damage is really easy and should be within the capability of many people.

If you are just changing joints it is very straightforward but if you want to strip the joint check for wear and re-grease with a high quality CV grease it is still not too difficult.

There are many CV joints now on the market some are excellent and other quite poor. We only use genuine GKN.

[Gary71]

The four joints were £188 all in. But I'm going to fit them myself just due to time constraints yesterday and not wanting not to drive back to Coventry to pick them up on another day.

[Uk911]

I paid 256 plus vat and delivery one way, I dropped them off on way down country, 4 cv fitted and boots on and shafts painted all up ready to fit to the car......hope that helps..mark

[911hillclimber]

On my hill climb 915 box with March F2 CV's (flat faces on box and CV joints) I use engine gasket (Blue Hylomar) paste and GKN CV joint grease in a tube (from Demon Tweeks or Merlins).

There are 6 bolts, no dowels, 220 lbft going through them with 12" wide slicks.

No leaks, no issues, but not exactly road miles...

[Brewster]

I paid 256 plus vat and delivery one way, I dropped them off on way down country, 4 cv fitted and boots on and shafts painted all up ready to fit to the car......hope that helps..mark

Many thanks, and as I hoped. I'll send them down to him for an appraisal and refurb. He just wouldn't give even a rough price to the nearest £100, even though I promised not to hold him to it should they have turned out to be totally FUBAR, which I'm sure they're not.