Rear Axle

[hallowsgate]

My Marina 1800 TC-based SWB Marlin was put together in 1984 and if my memory serves me right, the rear axle was slotted in without any refurbishment - well, I was a cash-strapped spotty youth back then! Some 42,000 miles later and the back axle is beginning to make some squeaks and chuffing sounds, with a fair amount of oil now leaking around the diff. At the last MOT, I was warned that the half shafts were on their way out.

It's a while since I've had to get my hands dirty but the onset of dark nights seems a good time to get stuck back in. I was wondering how big a job it would be to rebuild the rear axle and what parts I would need to replace? Would any special tools be required? Or would it be more cost-effective/sensible to have it done professionally? Any advice on where to go and what it might cost?

I also thought that if I could get hold of a spare axle, I could rebuild it before swapping it over - I've put an ad in the wanted section if anyone can help.

(I assume I need an axle from an 1800 and that it's not interchangable with a 1300 item?)

All comments, advice or encouragement would be appreciated.

Thanks. Bruce

[dogoncrazy]

Re: Rear Axle

Axles are same apart from diff ratio.The 1300 uses a 4.1/1 and the 1800 a 3.89/1 A number of special tools are required for rebuilding the diff[Dial test indicators and the like for setting backlash] Apparantly the diff from 1850 Triumph dolomite is the same as are the halfshalfs and can be obtained from Rimmer Bros BUT at a price! Contact Kris Kenmuir -Hogg[see for sale items] as he has a number of axle parts.The axle in modified form was also used in Lotus/Caterham sevens and some parts can be obtained from Caterham themselves but again at considerable cost!

[lil_red_roadster]

Re: Rear Axle

The axle is a Triumph unit, almost identical to that used in the Dololite and Toledo. The 1.8 diff is a 3.63:1 ratio - I can't recall if it was the later 1.3 A+ engine or the 1.7 that had the 3.89 ratio. Caterhams were shipped with the latter IIRC. The Haynes manual covers what you need to do but there are some other special tools required, notably a stretcher to remove the diff from the carrier. Also it is strongly recommended to get hold of the correct puller for the hubs. Canley Classics sell these but you could probably get 2 spare axles for the cost of it..! A standard 3-leg puller is next to useless and there is the danger that you may deform the hub-flange. Might be worth asking Canley Classics or similiar Triumph specialist for a quote to rebuild it.

[dogoncrazy]

Re: Rear Axle

Sorry Jez but I have to disagree on the subject of ratio's. I have an 1800 diff {that's what it came out of] on the bench in my garage and it's stamped 11/40 ie 3.89:1, my original diff in my 1300 engined roadster was a 37/9 ie 4.1:1. The info I have on various diff ratio's is as follows:
Marina/Ital 1300 4.1:1
Marina/Ital 1700/1800 3.89:1
Marina 10 cwt van 4.556:1
Triumph Dolomite 1300 4.1:1
1500 3.89:1
1850 3.63:1
Auto 1850 3.27:1
Toledo 1500 3.89:1
TR7 4 speed 3.63:1
Having said all that I wouldn't put it passed BL to use whatever was available in some cases!![no pun intended]

[neilryland]

Re: Rear Axle

I have to disagree with you Alan, my rear axle came off a 1800 Marina & is 3.63:1 (I counted the teeth to prove but can't remember the numbers - it was stamped on the crownwheel as well).

I recently fitted a refurbished casing (bought from a scrapper as a complete axle - good for spare halfshafts etc...) and that one had a 3.89:1 diff, this one came off an 1800 Ital. So I put my 3.63 into the refurbed casing.

So I think some versions of the 1800 Marina were fitted with 3.63's.

Like you say - it was BL. Anything that fits will do !!!.

But at least I do now have a useable spare diff (even if it is a 3.89), halfshafts and brake backplates. I threw away the 30 year old rusting casing from my original build.

[dogoncrazy]

Re: Rear Axle

Thanks Neil, guess my info is incorrect after all. It was I admit based on taking apart what were 'supposedly' 1800 axles over a number of years. Just goes to prove that we should never beleive all that we are told .Apologies Jez for doubting your info, guess the beer is on me next time we meet!

[amalgamated users from prior forum]

Re: Rear Axle

Message originally posted by: Don
Alan: 40/11=3.63 not 3.89.

[lil_red_roadster]

Re: Rear Axle

No worries Alan - free beer is always acceptable..maybe at the Llawnroc next summer?! The ironic thing about debating the Triumph axle is that my grandad was one of the engineers who designed the tooling to produce it originally..NB he didn't design the axle though, so don't complain to me about it's shortcomings..!

[dogoncrazy]

Re: Rear Axle

Don
I think I'm having more than a senior moment!! thanks

[hallowsgate]

Re: Rear Axle

Thanks for all the technical feedback. Can't help feeling i should either get hold of an old axle and try taking it apart to see what's involved (rather than disabling the roadster) or put my hand in my pocket to have it rebuilt.

I'll try Canley Classics, Jez. Can anyone recommend anyone else?

Thanks all.

[neilryland]

Re: Rear Axle

Bruce,

The axle is a doddle to get apart in-situ.

Just remove the brake pipes, handbrake cables, the 4 bolts from the brake backing plates (4 each side) and withdraw the half shafts - might need a slide hammer although I never have. Then the diff can be removed by just removing all the bolts.

If the casing is in reasonable condition you can put in either of the diffs - 4.11, 3.89 or 3.63. Overhauling the original is a bit tricky though. You could also change the halfshafts as well if needed, although getting the hubs of the ends can be a B#####d, I took mine to a machine shop where they used a 10ton press + heat - they came off with a hell of a bang !!!.

[b_caswell]

Re: Rear Axle

Just to add to the ratio discussion the 1850 Dolly AUTO had a 3.27 diff that also fits. If you cant borrow a stretcher for the diff, it is possible to squeeze the casing from top and bottom with a large G type clamphtis allows you to get the shims back in. Pulling the half shafts can be done with the car on axle stands and putting a wheel back on with only a couple of turns on the nuts then use the wheel (carefully) as a slide hammer. The half shafts may have some play in the bearings but also watch for the bearing moving on the shaft as its only a press fit. The oil leak from the pinion can be dealt with without removing the unit or stripping. The oil seal can be changed by removing the drive flange. But it may be worn due to play in the pinion bearing which can be felt as an up and down movement at the drive flange.