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Dennis vessel hubs- cap head torque

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I am in the process of fitting new hubs to my TR6. Beautifully engineered as supplied by Dennis Vessey. Since the driveshafts are too large to pass through the trailing arm they have to be assembled on the car.

 

3/8 unf high tensile (12.9) are supplied to attach the driveshafts to the hubs. I have mailed the supplier for advice on what to torque these bolts to, but as yet no reply.

 

I have had a fumble through various web pages but there is no substitute for advice from real people.

 

50nm too much ?

 

Regards

 

Gav

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Err...no more than 16 lb ft torque, there's 6 of them and the studs are in shear and will never fail, it's the fixings into the poxy alloy trailing arms which will go first.

 

More importantly how do you plan to machine the hub stud holes out in the trailing arm because they are 5/16 th UNF (ie 1/16 th smaller than your studs and need retapping to 3/8th UNF to accept your new studs) unless a 5/16 - 3/8 staggered stud is supplied. Even if the holes don't need drilling out it's as well to engineer a jig to prevent the tap leaning when retapping the arms, the studs need to be square at 90 deg to the arm in two planes otherwise the hubs won't fit over the studs. The original hole sizes in the hubs were of course 5/16th dia and a close fit onto the stud, close enough fit so as to prohibit a hub fitting over the studs if you have a 5thou lean on the stud into the trailing arm, so beware of freehand tapping, unless you are well practiced. I'm a time served toolroom engineer and I'm wary of such a practice without a jig, do it once do it right.

There's reams of advice on hub fitting accessed by using our search facility, including the torques settings, come out of New Content and use the general Forums setting try a search under Trailing Arms, there's dozens of posts there on how to do it etc.

 

Mick Richards

Edited by Motorsport Mickey

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Sorry Mick I may have not been clear with my post. The cap head bolts in question attach the driveshaft to the drive flange on the back of the hub. The design of the hub is different to the original as it has a flat face rather than a yoke. The driveshafts have flanges either end. As supplied with the hubs from Dennis Vessey.

 

I have replaced the trailing arm studs using the jig from CDD.

 

Regards

 

Gav

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See what you mean now Gav, hope somebody with experience chimes in.

 

Mick Richards

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Gav.

 

Are these the Quaife hubs or the cosworth type? Are you saying the drive shafts come with a uj yoke that just bolts to the hub?

 

Cheers

 

Dave

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They are the Quaife version. The driveshafts have a flat flange either end. So it bolts to back of the hub, just as it does to the diff. Only difference is the back of the hub is drilled / tapped.

 

They are supplied with 3/8 unf high tensile cap head bolts but I have found various suggestions on torque settings online.

 

Had some spare time today so wanted to get it assembled. Will be calling Dennis Vessey tomorrow to ascertain the torque setting as he supplied them.

 

 

Regards

 

Gav

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Gav,

I have the hubs and drive shafts that you describe on my race TR6 and have had for many years without any problems.

They are however a pain to install as I've found when carrying out off season rebuilds on the car or had them dismantled just to gain access to the grease nipple within the trailing arm.

 

I've found that, awkward as it sounds, it's best to remove the trailing arms from the car. Trying to locate and tighten the cap head screws with the arms in place was a nightmare.

Bolt the hub to the face of the trailing arm, I've put 5/16" UNC helicoils in mine, using recommended torque.

Then hold the trailing arm in a vice, hub downwards.

Offer the drive shaft flange down into the trailing arm, locate on the hub and insert the cap head screws vertically downwards. I've used the serrated hard washers each time as well. It's much easier to engage the cap head screws this way. To tighten them I've used an allen key (8mm I think) on a 3/8" drive ball ended socket extension as they are a bit slimmer than a 1/2" drive extension to manaouvre (SP?) past the shaft UJ.

I've then used a 3/8" up to 1/2" adaptor so that I could use a 1/2" drive ratchet to get a decent leverage, approx. 11" - 12" long. Comforted by the fact that they are HT cap head screws into high quality steel hubs I've then adopted the "give it as much welly as you can" technique without any reference to specific torque setting. Don't be tempted to use a long "cracking bar" for more leverage.

Anathema as this may seem to some of you out there, it's worked for me.

 

You then have the problem of the assembled trailing arm/hub/drive shaft unit being a bit heavy and unwieldy to refit to the car but possible on your own with a little patience. The weight and unwieldy balance can be reduced by removing the inner end of the drive shaft before refixing the trailing arm then refit the inner shaft underneath the car before bolting up to the diff flange.

 

Hope this helps and good luck.

 

If you do get any advice on torque from Dennis Vessey please let us know.

 

Dave McD

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I've got the same drive shafts and yes they are a major pain to fit, I was advised to fit the drive shafts before fitting the diff, that way you can get your head where the diff lives and get your eye in line with the hub in the trailing arm and get everything lined up. Only problem is I got that piece of good advice AFTER I had fitted the diff and AFTER I had spent a 'challenging' afternoon getting one drive shafts all bolted up by the 'feel method'! so I was stuck ! and had to spend another afternoon getting the other drive shaft fitted......... also by feel.

 

Not a great experience but you live and learn ! :o

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Gav,

I have the hubs and drive shafts that you describe on my race TR6 and have had for many years without any problems.

They are however a pain to install as I've found when carrying out off season rebuilds on the car or had them dismantled just to gain access to the grease nipple within the trailing arm.

 

Dave McD

Hi Dave,

would it be possible to drill a hole in the trailing arm coincident with the shaft grease nipple.

 

Roger

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i also have these fitted. The early versions were a pain i believe but the later which came out about 3 years ago are a straight fit . no modifications required.

 

Roy

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I had spent a 'challenging' afternoon getting one drive shafts all bolted up by the 'feel method'! so I was stuck ! and had to spend another afternoon getting the other drive shaft fitted......... also by feel.

 

Not a great experience but you live and learn ! :o

Graham, with the trailing arms off the car it took less than an afternoon to complete both sides.

Dave

 

 

Hi Dave,

would it be possible to drill a hole in the trailing arm coincident with the shaft grease nipple.

 

Roger

Roger, never considered that but I'll investigate. Not too keen to drill any hole that might weaken the already fragile trailing arms. With the high cornering forces of a race car I've had cracks develop at the bottom of the outer face which I've had to have welded up and at the same time I had a plate welded underneath over the void in the aluminium casting to better spread the loads. I check the tightness of the 6 hub fixings into the trailing arm before each race to be sure.

Dave

 

 

i also have these fitted. The early versions were a pain i believe but the later which came out about 3 years ago are a straight fit . no modifications required.

 

Roy

Roy, lucky you. See you at Race Retro.

Dave

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Hi Dave,

the top surface should be under compression most of the time - that may be a suitable area if accessible.

Or the rear 3-o-clock position. Possibly weld a boss around the hole to bring it back to strength is worried.

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Hi Dave,

the top surface should be under compression most of the time - that may be a suitable area if accessible.

Or the rear 3-o-clock position. Possibly weld a boss around the hole to bring it back to strength is worried.

 

Good idea Roger, I'll look into it - both literally and metaphorically.

Dave

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I have a feeling, if you unbolt the driveshaft from the diff. You can dress the driveshaft to one side and the grease nipple in the outer uj will present itself.

 

Regards

 

Gav

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To conclude my original post on what torque setting is read for the cap head bolts attaching the driveshaft to hub. I have had a somewhat ambivalent response from the supplier.

 

Some searching of engineering sites suggests 55nm would be appropriate. I am done thinking about it now and they are assembled.

 

Interestingly I was not expecting any more hiccups. Famous last words......

 

I attempted to re-fit my wire wheel adaptors only to find they foul the hub. Not the end of the world I know, but it would have been nice to be warned in advance of the purchase.

 

6mm spacers on route from revingtons now.

 

Gav

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I contacted Dennis Vessey via phone directly and asked him regarding installation and torque. His answer, use LocTite and tighten the bolts as much as possible. Those are high strength bolts and hubs, so I used some engineering judgement. Time will tell. The installation can be done from the inside, with hubs installed. It's a hassle, but it works.

From Germany best regards....Jochem

Edited by JochemsTR

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I am in the process of fitting new hubs to my TR6. Beautifully engineered as supplied by Dennis Vessey. Since the driveshafts are too large to pass through the trailing arm they have to be assembled on the car.

 

3/8 unf high tensile (12.9) are supplied to attach the driveshafts to the hubs. I have mailed the supplier for advice on what to torque these bolts to, but as yet no reply.

 

I have had a fumble through various web pages but there is no substitute for advice from real people.

 

50nm too much ?

 

Regards

 

Gav

The key points here are that the H/T bolts supplied should have a lead in machined on to the end of the bolt i.e. at least two threads turned off and the bolt should have 8.8 numbers on the top face as far as the cap heads go if they are Unbrako, you will have great difficulty breaking them. They often have number on them as well. Lastly the type of material they are screwed into, usually governs what is the max torque that can be applied subject to the numbers on the top bolt face. Your local Fastener Shop should have a chart with the n/m that can be applied to each type of bolt.

 

Bruce.

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I contacted Dennis Vessey via phone directly and asked him regarding installation and torque. His answer, use LocTite and tighten the bolts as much as possible. Those are high strength bolts and hubs, so I used some engineering judgement. Time will tell. From Germany best regards....Jochem

 

 

Comforted by the fact that they are HT cap head screws into high quality steel hubs I've then adopted the "give it as much welly as you can" technique without any reference to specific torque setting. Don't be tempted to use a long "cracking bar" for more leverage. Anathema as this may seem to some of you out there, it's worked for me.

 

If you do get any advice on torque from Dennis Vessey please let us know.

 

Dave McD

Jochem,

Dennis Vesseys' advice is just what I said. It's not caused me any problems to date after approx. 10 years of use.

Dave Mc

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My biggest problem was I managed to dislocate my knee and tear my LCL whilst doing this job. All most inconvenient as the car is still in bits.

 

Happy days

 

Gav

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Let’s just say, my own fault to a degree.

 

Tidy workspace and all that!

 

Twisted whilst carrying the diff, my foot was planted. My knee twisted but my foot didn’t. There was a loud pop from my knee. Must have looked hilarious the ballet of me desperately looking for somewhere to drop the diff before falling over.

 

Couldn’t walk for a week...

 

Anyway, the mri scan reveals no major damage and time will be a healer. Apparently it is called a subluxation when your knee pops out and goes back in again.

 

Thankfully I changed the gearbox last year

 

Gav

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