The Triumph Dolomite Club - Discussion Forum

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 Post subject: Rear axle leak
PostPosted: Mon Aug 05, 2019 3:50 pm 
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Joined: Wed Oct 04, 2006 12:52 pm
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Location: In the colonies
Hi All,

I finally have my Sprint back competing State side. Currently doing autocross events. I have slick tyres on the car and after the last event the drums were full of oil. I've read about the gearbox seal modification but am wondering if there is also anything else that can be/has been done to mitigate the problem even more, such as better bearings giving the half shaft better support. I do not have to worry about any racing/homologation rules so am free to modify the axle if it will help.

Regards,
Mark

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 Post subject: Re: Rear axle leak
PostPosted: Tue Aug 06, 2019 12:45 am 
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Joined: Fri Oct 06, 2006 8:57 am
Posts: 566
Location: Auckland, New Zealand
Hi Mark
I started with the gearbox pinion oil seal modification and found that a vast improvement. However, I never raced with slicks, only circuit classic racing using Toyo and Dunlop treaded race tyres.

At one stage while I was racing I did manage to get hold of an axle that had been modified with support bearings midway along the halfshaft. Apparently that had been a very expensive modification! Unfortunately it didn’t last all that long (less than a couple of years) and then destroyed the C&P as well as the LSD. I do have a poor copy of a drawing that details how this was done.

I’ve never seen or heard of anyone making the thicker diameter Sprint halfshafts these days, but you could try contacting Rob MacGregor at Sprintspeed in the UK, or Ken Wood. He has posted on here but not recently. Both are active in motorsport in the UK.

I ended up modifying a Ford Capri 3L rear axle by welding on the Sprint axle mountings. Didn’t have to change the prop, but modified the Ford pcd on the half shafts to take Sprint wheels. LSD are cheaper and parts are available, as are upgraded half shafts. I used 3J Driveline in the UK for these. No real issues with this modification over many years.

Might be simplest to start with the oil seals and see how you go!

Geoff


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 Post subject: Re: Rear axle leak
PostPosted: Tue Aug 06, 2019 3:44 pm 
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Thanks for the input Geoff.

I think that is sound advice, start with the seals. I'll give it a go and also look for a small rear axle over here as a potential replacement. I'll probably have to look for something japanese as all the US stuff is just plain massive!

Cheers,
Mark

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 Post subject: Re: Rear axle leak
PostPosted: Wed Aug 07, 2019 12:17 pm 
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Joined: Sun Apr 06, 2014 9:49 pm
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Location: Northwich
Much has been said on this subject recently and after changing all four seals on my Sprint, still have a leaking off side hub.

After all the effort and cost I've gone to to sort it, all to no avail, it's soul destroying.

I suspect, as has been said here that it's the drive shaft flexing...

https://forum.triumphdolomite.co.uk/vie ... f=4&t=7920

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Was searching for my first Sprint UUW 410M to get back and restore....but after some excellent work by Detective Matt of the Vivas, it has indeed been traced to Llandudno where it appears to be waiting to undergo a full restoration and hopefully a happy life!


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 Post subject: Re: Rear axle leak
PostPosted: Mon Aug 19, 2019 7:32 pm 
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Would anyone happen to have the ST halfshaft specs and/or drawing available to share?

Cheers,
Mark

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 Post subject: Re: Rear axle leak
PostPosted: Fri Aug 23, 2019 7:06 am 
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Location: Auckland, New Zealand
Short answer is no and I've never seen anything. I've relooked through the copies of old homologation papers I have and nothing mentioned other than simply 'uprated rear axle' in Group 2. I suspect this is more of a modern issue as period racing tended to use narrower tyres that slid more than modern sticky rubber we use. Hence it might have been more common in Group2?

Can only suggest you contact the people I mentioned above, also Cambridge Motorsport as I believe they prepare some racing Sprints in the UK. Be interested to see what you can find out.

Geoff


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 Post subject: Re: Rear axle leak
PostPosted: Mon Aug 26, 2019 1:22 pm 
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I replaced the seals in the axle, it already had the gearbox seals in but I did them anyway. there was no grease in the bearings, i suppose it got washed away by the oil.

Anyway I reassembled carefully and after one autocross yesterday all seems well from the outside. I'll pop the drums off again soon to see if there is any sign of a leak.

Cheers
Mark

PS excuse the condition, it goes better than it looks!

Image

Image

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 Post subject: Re: Rear axle leak
PostPosted: Thu Sep 12, 2019 9:34 am 
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Joined: Fri Feb 02, 2007 10:27 am
Posts: 108
Location: U.K.
Mark,

I have 'uprated' half shafts that I have fitted in my Sprint axle and I am guessing that it is an ST copy. Axle remaines on the shelf in the garage for a decade but all went in ok as I remember, but remains untested. I would also hazard a guess that Triumph used to raid the parts bin to find suitable bits. We already know that T2000, Stag and TR6 parts are used on the axle.
I have something in my mind from the dim and distant of this half shaft being from a TR4? afterall the leather! oil seal would indicate that its not a new for the 70'S design!
My half shafts do not have the reduced diameter machined over the length of the half shaft. That is to say that over the full length of the half shaft the diameter is exactly the same as the spline? dia.

Hope this helps.


Phil.


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