Play in axle splines

[foster461]

Winter has been slow to arrive here in New England but my winter projects are under way. This years scheduled work includes overhauling the differential (already delivered to John Esposito in CT) and refurbing the rear chassis and crossmembers while the diff is out. While I had easy access to the drive shafts I checked them both for worn UJ's and splines and I find one side does have a bit of play in the splines. I can grip both halves of the RHS drive shaft and rotate the inner half and hear/feel the slight movement in the splines. The UJ's seem fine. The other side (LHS) is fine, no play at all.

 

I'm wondering if this is something I should fix now or if a slight amount of wear is acceptable ?. I had these apart this summer and they were well greased so I dont think it is a simple lube problem.

 

While I think of it I have one other question.. I noticed that there is a hole in the rear of the rear crossmember that has a rubber grommet in it. I'm struggling to think of why there is a hole there and why it has a grommet in it, any ideas ?.

 

Stan

[Richard Crawley]

Stan

Some wear in the splines is inevitable particularly when you consider how old most of them are now, unless it clonks badly I wouldn’t worry about it too much. I use Castrol Heavy grease (but anything similar will do) to re-pack mine every year or so. It’s very thick, having a consistency similar to a light tar & quietens things down a treat.

 

The only other option is a good second-hand unit (increasingly difficult to find) or one of the remanufactured drive shaft designs on offer. These have the benefit of better/higher power transmission & prevent spline lock but they are bl**dy expensive & unless your putting down much more power than the standard car, go racing or still have loads of money left over from Christmas (thanksgiving), they are a bit of a luxury.

 

Which cross member & which side of the car was the grommet!

[foster461]

Stan

Some wear in the splines is inevitable particularly when you consider how old most of them are now, unless it clonks badly I wouldn't worry about it too much. I use Castrol Heavy grease (but anything similar will do) to re-pack mine every year or so. It's very thick, having a consistency similar to a light tar & quietens things down a treat.

 

The only other option is a good second-hand unit (increasingly difficult to find) or one of the remanufactured drive shaft designs on offer. These have the benefit of better/higher power transmission & prevent spline lock but they are bl**dy expensive & unless your putting down much more power than the standard car, go racing or still have loads of money left over from Christmas (thanksgiving), they are a bit of a luxury.

 

Which cross member & which side of the car was the grommet!

 

Thanks Richard, the wear is slight but using heavier grade grease may do the trick.. I have already exceeded my allowance for this year (several times over) so deferring this repair for a while would help some higher priority projects. I'm curious to know how you manage to re-lube these annually. That sounds quite tedious if you are disassembling the whole thing.. do you do this in situ ?

 

The crossmember with the hole/grommet is the rear diff mounting crossmember. The hole is in the vertical face that is next to the trunk wall and is in the center of the crossmember. If this is not clear I'll post a picture.

 

Stan

[Richard Crawley]

I'm curious to know how you manage to re-lube these annually. That sounds quite tedious if you are disassembling the whole thing.. do you do this in situ ?

 

Stan

I do it as part of the car’s annual service regime & pre-MOT check. Once you’ve got the car on axle stands with the road wheels & brake drums removed, it’s a simple job to remove the complete driveshaft; just undo the 6 hub securing nuts & the 4 inner U/J bolts & the drive shaft comes out as a complete unit – 10 minutes if that! It’s then onto the bench for the messy bit of separating the splined unit, cleaning, re-lube, check the general condition of the rubber bellows & hub bearing & back on the car.

 

Re the hole/grommet; there are 2 holes in the centre of this member, one in the rear face (which I believe is the one you see) & one on the top. These are not used for anything as far as I’m aware & I assume are just part of the original manufacturing process; sounds like someone has put a grommet into one or possibly both of them but as to why, I don’t know!

[Eyetee]

Stan

I am faced with a similar dilema, my nearside (left) driveshaft has a little play. Have researched upgrades and they all come at a cost starting around £200 a side (Revington/TrEnterprises).

 

The Bill Piggott "How to restore a TR6" suggests that the drive shafts are the same (RKC454) and therefore interchangable, switching shafts has the benefit of driving on the other side of each spline. Also recomends Molybdenum grease for the splines. Emphasises new nyloc nuts or spring washers with every assembly and to place the nut not the bolt on the U/J side of flanges. He also mentions the "Triumph IRS rear twitch" a symptom of worn splines, high torque causes drive shafts to lock preventing suspension movement until either a bump or drop in torque allows a sudden readjustment "Twitch". Having yet never driven an IRS Triumph I cant comment.

 

Personally I'm following Bills advice to switch sides with the drive shafts, replacing all U/js, new rubber bushes and a set of lowered springs. All this bar the U/Js arrived with the rebuild and so any further upgrades can be done later as an when deemed necessary.

 

Best regards

 

John

[foster461]

Stan

I am faced with a similar dilema, my nearside (left) driveshaft has a little play. Have researched upgrades and they all come at a cost starting around £200 a side (Revington/TrEnterprises).

 

The Bill Piggott "How to restore a TR6" suggests that the drive shafts are the same (RKC454) and therefore interchangable, switching shafts has the benefit of driving on the other side of each spline. Also recomends Molybdenum grease for the splines. Emphasises new nyloc nuts or spring washers with every assembly and to place the nut not the bolt on the U/J side of flanges. He also mentions the "Triumph IRS rear twitch" a symptom of worn splines, high torque causes drive shafts to lock preventing suspension movement until either a bump or drop in torque allows a sudden readjustment "Twitch". Having yet never driven an IRS Triumph I cant comment.

 

Personally I'm following Bills advice to switch sides with the drive shafts, replacing all U/js, new rubber bushes and a set of lowered springs. All this bar the U/Js arrived with the rebuild and so any further upgrades can be done later as an when deemed necessary.

 

Best regards

 

John

 

Richard: you are a brave man pulling these out every year. I would worry about the hub studs (I already have several helicoiled) but I guess if you have them locktited in there is less danger in them getting loose and wearing out through frequent dismantling. I'll consider your approach though, I did notice that despite the intact rubber boots there was a lot of **** in the sliding parts and a good clean every year or two would not hurt.

 

John: good suggestion for rotating the axles. I'm familiar with the torque lockup/twitch syndrome although never experienced it myself. I tend to be less agressive with the welly these days so I'm not too concerned about that unless it gets worse with increased slop.

 

Stan

[Richard Crawley]

Richard: you are a brave man pulling these out every year. I would worry about the hub studs (I already have several helicoiled) but I guess if you have them locktited in there is less danger in them getting loose and wearing out through frequent dismantling.

 

Stan

All of my studs have been fitted with Loctite into Helicoil inserts for many years as several were already damaged when I got the car back in 1975. Since I replaced them the studs have been fine & never unscrew (rather than the nut coming off) & fairly frequent removal avoids the nuts seizing.

 

Damage is generally caused by over tightening which strips out the alloy thread. The problem is that many just don’t appreciate how little torque is required &, ideally, a torque wrench should be used but many just keep leaning on the end of a ratchet bar. Personally I use a socket on the end of a ½” drive extension bar & just tighten using my bare hand (no lever); I checked the applied torque once by doing it this way & found it was just about right.

 

It goes without saying you should always replace Nyloc nuts or spring washers when removed, particularly on critical components.