Sprint axel - Overhaul advise?

[bazyerma]

Hi

I have just picked up a sprint rear axel to overhaul for my engine conversion. The plan is to strip it, get the casing blasted and powder coat, and fit new bearings and seals.

I will be making a rear disc conversion (using the MG TF calipers, discs and stub bolts I already have fitted to my 1500 axel but with new brackets) so I will be removing the rear drum set up (As before, I don't care if you think its a pointless upgrade, it looks cool and works great with my Tracker jack front brakes so would be a shame not to keep them).

Any advises on striping the axel, or anything to look out for? Parts wise it should be easy but is there any upgrades on the seals I could do?

Thanks for any tips!

Regards

Barry

P.s Should i get the drums blasted at the same time, maybe they will be off use to someone (if they collect from Aberdeen!)?

[xvivalve]

Take care which bearings you buy, there are two distinct qualities as shown by this link:

https://rimmerbros.com/Item--i-GHB166

I have a limited quantity of NOS Unipart GHB166 which are the far superior Timken brand, but my price is by comparison a very reasonable £35 each inc postage!

[new to this]

may be an idea to fit a oil drain plug ?

Dave

[cleverusername]

I would be a bit wary of those MG TF calipers, we have had problems with them on my fathers MGF. They don't like winter layups and the handbrake mechanism in them is not user serviceable. Once it starts to seize up, we have found the only effective repair is to buy a new caliper, which is a bit of a pain.

[new to this]

I would be a bit wary of those MG TF calipers, we have had problems with them on my fathers MGF. They don't like winter layups and the handbrake mechanism in them is not user serviceable. Once it starts to seize up, we have found the only effective repair is to buy a new caliper, which is a bit of a pain.

I fitted Rover 45 calipers to mine,there almost the same as MGF,so far not had any trouble,but will keep an eye on them,
When your Father lays his car up over winter does he pull the hand brake up ?

Dave

[cleverusername]

I would be a bit wary of those MG TF calipers, we have had problems with them on my fathers MGF. They don't like winter layups and the handbrake mechanism in them is not user serviceable. Once it starts to seize up, we have found the only effective repair is to buy a new caliper, which is a bit of a pain.

I fitted Rover 45 calipers to mine,there almost the same as MGF,so far not had any trouble,but will keep an eye on them,
When your Father lays his car up over winter does he pull the hand brake up ?

Dave

He left it on but to be fair we had no issue disengaging the handbrake. The problem was, once the brakes got corroded over winter, we couldn't get full movement back in the mechanism once they were off and the handbrake was no longer effective. It failed the mot.

They just don't like being out in the weather without use.

[Carledo]

Around 80% of disc rear cars use some version of this caliper for the handbrake (posher stuff uses the far superior "drum in disc" system)

It's not a brilliant system by any stretch of the imagination and usually is only adequate rather than excellent. But it's not really a problem. Though i'd recommend upgrading to dual circuit brakes if your car hasn't got them already. That way, come MOT time the handbrake only has to make 16% of 1G, rather than a single circuit system which demands that the handbrake make 25%.

It's not a hard thing to work with though, once you understand it. Forget the hydraulic side, that's just a normal single piston floating caliper, nothing to it. The handbrake bit is the bit that fails and trust me, you don't need to leave it all winter for it to get sticky, they regularly jam up and become inefficient in daily use. But it only needs a good squirt of plus gas (other penetrating fluids are available) and a couple of minutes working the arm to get it all functioning well again.

Why do they stick? 2 reasons, both connected to the fact that handbrake actuating arm is solely responsible for the self adjustment of the mechanism that copes with pad wear. Reason 1, the pads wear so slowly that the arm and internal mechanism doesn't get enough use to keep everything free and Reason 2 the actuating arm is out in the dirt and muck and MUST move over it's entire travel and return fully to work the self adjuster. The caliper HAS a spring to assist the return of the arm but it doesn't take much gunk to overcome the spring then the arm stops returning fully , self adjustment stops, but the pads continue to wear from footbrake use (yes, and from binding when the handbrake sticks on a bit) and soon enough, the handbrake no longer works.

An astute driver will notice the travel in the lever increasing and get to it before the problem gets serious.

Fixing it is simple, disconnect the inner cable from the operating arm and smother the spindle area with your favourite penetrating fluid. Some operating arms have a 13mm nut retaining them on the spindle and some don't, if it does, you can use a long 13mm spanner to gently work the arm back and forth (being especially careful on the anticlockwise or "undo" phase of the nut) if there isn't a nut, a large mole grip on the arm works. Keep working it until full return under spring action alone is possible. You will notice that as the thing starts to return fully, the travel in the "on" direction reduces proportionally till there is only 1/2 an inch or so of movement. Then it's done, slip the cable back in and you are in business. Most cars don't require wheel removal to do it, some, like SWMBOs Picasso, don't even need to be jacked up! 10 minutes per side or less! Seemples!

Steve

PS since SWMBOs Picasso is automatic, the handbrake only gets used once a year - at MOT time! So this is a regular job for me on the pre MOT service!

[xvivalve]

...and don't forget the Club now have these in stock:

https://forum.triumphdolomite.co.uk/vie ... rs#p337825

[soe8m]

You have a casing spreader? You can't overhaul successfully without one.

Jeroen.

[Carledo]

You have a casing spreader? You can't overhaul successfully without one.

Jeroen.

Yeah, what Jeroen said ^^^^^^^

I was gonna mention that and got sidetracked with the handbrake!

This Salisbury style diff is a monster to overhaul and bits are short. Mad Mart has (or had) a diff spreader, but even with one, it's a PITA to build the diff and come out with something quiet.

Not much use to you where you live, but I have a guy for this who is much more experienced than I am! Like Clint Eastwood said, a man should always know his limits!

Steve

[bazyerma]

I would be a bit wary of those MG TF calipers, we have had problems with them on my fathers MGF. They don't like winter layups and the handbrake mechanism in them is not user serviceable. Once it starts to seize up, we have found the only effective repair is to buy a new caliper, which is a bit of a pain.

Hi

Thanks for the warning, but they have my car for 12 months with no problems (although only do 1500 miles and leave it in a garage over when not in use), so I think the issue is your dads car.

Regards

Barry

[bazyerma]

You have a casing spreader? You can't overhaul successfully without one.

Jeroen.

Yeah, what Jeroen said ^^^^^^^

I was gonna mention that and got sidetracked with the handbrake!

This Salisbury style diff is a monster to overhaul and bits are short. Mad Mart has (or had) a diff spreader, but even with one, it's a PITA to build the diff and come out with something quiet.

Not much use to you where you live, but I have a guy for this who is much more experienced than I am! Like Clint Eastwood said, a man should always know his limits!

Steve

Hi Steve

Do you have a link to a photo of what I need?

The plan was just to get the diff out, get the casing blasted and painted and fit new wheel bearing and seals. I am now guessing its more involed than the 1500 axel?

Regards

Barry

[Carledo]

You have a casing spreader? You can't overhaul successfully without one.

Jeroen.

Yeah, what Jeroen said ^^^^^^^

I was gonna mention that and got sidetracked with the handbrake!

This Salisbury style diff is a monster to overhaul and bits are short. Mad Mart has (or had) a diff spreader, but even with one, it's a PITA to build the diff and come out with something quiet.

Not much use to you where you live, but I have a guy for this who is much more experienced than I am! Like Clint Eastwood said, a man should always know his limits!

Steve

Hi Steve

Do you have a link to a photo of what I need?

The plan was just to get the diff out, get the casing blasted and painted and fit new wheel bearing and seals. I am now guessing its more involed than the 1500 axel?

Regards

Barry

I don't have a picture, but I think there is one somewhere on the forum.

Yes it's a complex diff, the spreader is needed to fit the diff with the correct carrier bearing shims into the case. If you are changing the carrier bearings, the shim thickness would need to be calculated (don't ask me how) Also the pinion shaft needs to come out separately once the diff is removed. Replacement officially involves using a new "crushable" spacer between the pinion shaft bearings, these are somewhere between very rare and unobtanium. there are workarounds for changing a pinion seal, but if fitting new bearings you'd have to have one. The other way to go is to fit a solid spacer, shims and castle nut like earlier TR4s and their cousins had, but finding those bits ain't easy either.

My advice is, unless it is obviously graunchy by hand, give it wire brushing and a coat of Hammerite or whatever and slap it in, maybe change the half shaft seals in passing and give it a road test. Then, if it ain't broke.....

Steve

PS i've put a number of used Sprint axles in various cars for myself and others, i've not had an unusably noisy one yet. Just lucky I guess!

[bazyerma]

Yeah, what Jeroen said ^^^^^^^

I was gonna mention that and got sidetracked with the handbrake!

This Salisbury style diff is a monster to overhaul and bits are short. Mad Mart has (or had) a diff spreader, but even with one, it's a PITA to build the diff and come out with something quiet.

Not much use to you where you live, but I have a guy for this who is much more experienced than I am! Like Clint Eastwood said, a man should always know his limits!

Steve

Hi Steve

Do you have a link to a photo of what I need?

The plan was just to get the diff out, get the casing blasted and painted and fit new wheel bearing and seals. I am now guessing its more involed than the 1500 axel?

Regards

Barry

I don't have a picture, but I think there is one somewhere on the forum.

Yes it's a complex diff, the spreader is needed to fit the diff with the correct carrier bearing shims into the case. If you are changing the carrier bearings, the shim thickness would need to be calculated (don't ask me how) Also the pinion shaft needs to come out separately once the diff is removed. Replacement officially involves using a new "crushable" spacer between the pinion shaft bearings, these are somewhere between very rare and unobtanium. there are workarounds for changing a pinion seal, but if fitting new bearings you'd have to have one. The other way to go is to fit a solid spacer, shims and castle nut like earlier TR4s and their cousins had, but finding those bits ain't easy either.

My advice is, unless it is obviously graunchy by hand, give it wire brushing and a coat of Hammerite or whatever and slap it in, maybe change the half shaft seals in passing and give it a road test. Then, if it ain't broke.....

Steve

PS i've put a number of used Sprint axles in various cars for myself and others, i've not had an unusably noisy one yet. Just lucky I guess!

Hi Steve

That's perfect, just the info I needed. I will get it blasted, clean out the casing of all the old oil, Change the half shaft seals and bearings and clart it in Hammarite.

Regards

Barry

[cliftyhanger]

That's perfect, just the info I needed. I will get it blasted, clean out the casing of all the old oil, Change the half shaft seals and bearings and clart it in Hammerite

Remember the sprint axle is a very different beast to the other dolly axles. You cannoy just pull the shafts and pop the diff out, the diff is built into the axle case.

A workaround for teh collapsabel spacer is to just get some shims and use thise with the old spacer, giving you a bit of extra to squash down. Kippings did that with the small chassis diffs when the collapsable spacers were unobtainable. And I had a 3.63 built with solid spacer to replace the collapsable one, that would have been early 90s.