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Vit Mk2 Rear Diff Removal


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Hi all,

I'm planning to swap out the rear diff on my 1969 Mk2 Vitesse, long story, don't ask.........

So, the first simple question - Can I remove it without dismantling the whole rear end set up (leaf spring etc)?

Secondly, any hints, tips, best order of removal, gotchas, and lessons learned regarding doing this?

Having read the various stories about the rear leaf spring and the fun that ensues refitting I'm hoping I don't have to enjoy that experience any time soon

Any help and advice gratefully received

Thanks in advance folks :-)

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never tried this but if you drop the prop, and remove the output shafts ( which involves undoing the drive shafts)

you can drop the front support and remove the diff assy  from the rear case leaving the rear case with the spring attached ans still supported by the two rear bushes

never tried this and it may be a right bum steer to attempt but nothing ventured nothing gained 

there will still be a good sprung load on the shafts which may take some effort to disengage the coupling to allow short shaft removal

you cannot remove the front plate ( 4 bolts ) without first removing the coupling flange

just some  thoughts 

Pete

 

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I replaced my diff on my roto gt6 mk 3 without removing any of the rear suspension (Plus I did not need a spring lifter) so I know it can be done on a gt6 mk3 as far as I know all the roto cars have the same set up? If I'm right I'll post how I did it.

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Hi Steve - the simple answer is yes you can. See my method, which works, below.

Gav. 

I have a Mk2 Vitesse ( Rotoflex) and previously have removed/replaced the diff using a spring lifter several times in the past, but decided to try another way last time I did the job, as described below. It may sound complex, but is easier than it sounds and saves a lot of time. However, please do not attempt this method if you are in any doubt about your abilities.

 

Slightly loosen,the rear wheel nuts. Jack up the car under the diff and support on axle stands under the vertical links.Then remove the rear wheels. It's very important to position the axle stands directly under the wishbone's outer trunnion bolt 'tube' in the middle of the wishbone.  Lower the car very carefully onto the stands, checking the final resting position of the wishbones on the stands ( As the spring takes the weight,it will tend to flatten out slightly, so constantly check the stands position until the cars' full weight is safely supported. Check and check again that the car is properly and firmly supported. 

Remove the spring fixing access plate. Find a couple of bits of wood, about 2" x 2" x 3"  ( from memory) Then position these on top of the spring, directly next to the the outer edges of the spring clamp plate. You should be able to 'fiddle' these blocks into position either through the spring clamp access hole and/or reaching into the tunnel.  The idea is that the wood blocks should be a snug fit between the top leaf of the spring and the underside of the spring tunnel - to stop it moving up when you remove the spring clamp plate/nuts. Ensure that the blocks are firmly wedged in position. Then position the trolley jack under the diff to just take the weight, but no more, Do not allow it to jack the car off the axle stands. You can now remove the bolts/nuts from the halfshafts and rear propshaft flange. I found that I did not need to remove the exhaust pipe,but you might have to on a GT6. 

Now you can gradually loosen and remove the spring clamp nuts and clamp plate. Then using the double nut locking technique unscrew the studs from the top of the diff. You can cover the stud holes with masking tape to stop dirt ingress into the diff. Then remove the diff mounting front and rear nuts/bolts.The diff is now ready to come out, by gently lowering the trolley jack. As I was doing the job on my own I also tied the diff with some strong rope, onto the trolley jack cradle to stop it sliding about. Note that the rotoflex couplings will be pressing inwards against the halfshaft flanges, so you will need to gently lever them apart with a large screwdriver or pry bar, whilst lowering the diff out.

Replacing the diff is largely the reverse operation, but ensure that the spring centering blind hole on the diff case locates properly with the spring fixing 'peg' on the underside of the spring.Refit the diff mounting nuts/bolts.Then refit the diff studs and spring clamp plate. Remove the wood blocks. Refit the spring access plate. Replace prop and halfshaft bolts/nuts. Don't forget to torque up all bolts/nuts. Have a cup of tea.

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The most difficult bit is usually lifting that weighty diff back into place.  Especially getting the two rear 'ears' into the cross frame.   Doing it with the spring and other gibbins in place sounds even more painful.

The lift is best done with a trolley jack, but the shape of the diff makes it roll off.   I use a simple wooden dolly between diff and jack.  The top is roughly shaped - bit of wood gouging and a cross piece nailed on - whole the bottom is flat for the jack pad.   See pic.

John

 

Diff carrier.jpg

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Thanks Gav,

That sounds promising, I guess loosening all of the diff drive shaft bolts and mountings in advance would help reduce the faffing about. I'll take the exhaust off as it's quite new and easy to remove, looks like it'll give me a bit more room to get in there and less to bash my head against :-)

I'll give it a go, I'm reasonably confident, having done a fair few jobs on various "old heaps" in my time.

Thanks John,

I'm always up for a useful hint and will happily make a wooden dolly to enable a smoother refit

Cheers

Steve

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32 minutes ago, Steve Brown said:

Thanks Mat

Is your method similar to Gav's or is there another approach to follow

Cheers

Steve

I did it a very similar way, I borrowed a very large Jack & axle stands, to raise the rear as high as possible. I had no problem releasing the half shafts, I took about 10 minutes getting it lined up with the mounts (the large jack helped with that) It was fairly easy for that type of job and took me about 7 hours in total by myself to remove & replace the diff.

Hope this helps

Mat

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I have done diff swaps on a 1500 spit in about 2 hours (last one was the day of the RBRR, 2008 woke up early, decided I wanted the diff that I knew was leakproof and silent fitted, rather than risk a slightly leaky and whiny one. Job done by 9am...) Rotoflex does add a chunk of time though, whatever way you do it....

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6 hours ago, Casper said:

The Triumph Repair Schedule gives 4.2 hours to "Replace Hypoid unit", but I'm sure my time would be nearer Mat's time.

C.

That's an hour for the work, an hour for tea break and the other 2.2 hours for the trade union meeting to decide whether or not to strike due to being asked to do jobs like this.

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i agree with the feedback. It is not possible to leave the rear set-up in place as it is under torque from the rear spring. If you undo the studs holding the spring to the diff, the spring will fly up at speed and pin itself against the bodywork. Not good. Use a spring lifter.

Dave

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i still like the idea of remove   short shafts  and bevel gear carrier from the diff housing leaving the diff hsg and  spring and  diff rear mounts in place to keep some support 

yes theres going to be some load on the hanging spring but if it works saves a lot of sweat

and a lot less weight .to lift       

pete

 

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3 hours ago, dave.vitesse said:

i agree with the feedback. It is not possible to leave the rear set-up in place as it is under torque from the rear spring. If you undo the studs holding the spring to the diff, the spring will fly up at speed and pin itself against the bodywork. Not good. Use a spring lifter.

Dave

Dave, read my post again carefully. The spring remains in place as the wood blocks stop it moving up towards the floor. Gav. 

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Gav - let us know how you get on, and good luck! It sounds good in theory, particularly the wood blocks, but I'm still having a few thoughts about the process and to be honest my first would be to remove the entire rear spring, no matter the additional bother. I'm trying to get my head around the idea that the spring is attached to the top of the diff, and the rear hub assemblies etc hang off either end. If you take the spring off the diff it's trying to compress upwards, hence the wood blocks - but what happens to the outer assemblies, given that the weight is all being taken by the rear shocks, and they're no longer secure by being bolted to the diff flanges? As Pete says, it's now a hanging spring, but what is it hanging from? If it can't push up, it will push down.... and you may have as much bother getting the assemblies to line up again in their new positions. Just be very careful and look after your fingers.

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we have 'shares'  in sticky plasters  

i remember as a youngster in 1966  removed the diff from my really rusty  59'   948 only to find ( there were no easy manuals around then)

that the short shaft had sheared and i didnt need to have removed the whole  diff at all.

it being  down the road in dads garage with a long extension and a dim lead lamp the best bit was the spring popping up and jamming against the floor   no idea how i got it back but much heave  Ho and jacking and levering , cant remember how the wheels hung, just found it would be easier left in the car , being clever afterwards is the learning curve 

dont ask how you shear a shaft in  a  948 rusty rocket.

Pete

 

 

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3 hours ago, trigolf said:

Dave, read my post again carefully. The spring remains in place as the wood blocks stop it moving up towards the floor. Gav. 

Gav, Just pointing out you have to be careful when you undo the diff/spring studs as there is a lot of force and energy in the spring. With blocks of wood that force is being place on the bodywork around the inspection opening.

Dave

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Dave,

Your advice is noted - and I agree that you have to very careful when working around a spring that's under load. However - as stated in my initial post - you do not undo any of the spring clamp retaining nuts until you have placed wood blocks that fit snugly between the top of the top leaf of the spring either side of the clamp plate and the underside of the body. So the spring can't move upwards. It also can't move forward or back as it's still attached at the spring eyes to the vertical links

Colin, The spring is supported in the normal fitted position, via the vertical links, and the shocks are still attached and the the suspension is supported by the axle stands under each vertical link. As stated - I have done this job successfully this way before with no problems. Finally, it's not me doing the job - it's Steve !

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  • 2 months later...
On 18 June 2018 at 8:05 PM, trigolf said:

Hi Steve - the simple answer is yes you can. See my method, which works, below.

Gav. 

I have a Mk2 Vitesse ( Rotoflex) and previously have removed/replaced the diff using a spring lifter several times in the past, but decided to try another way last time I did the job, as described below. It may sound complex, but is easier than it sounds and saves a lot of time. However, please do not attempt this method if you are in any doubt about your abilities.

 

Slightly loosen,the rear wheel nuts. Jack up the car under the diff and support on axle stands under the vertical links.Then remove the rear wheels. It's very important to position the axle stands directly under the wishbone's outer trunnion bolt 'tube' in the middle of the wishbone.  Lower the car very carefully onto the stands, checking the final resting position of the wishbones on the stands ( As the spring takes the weight,it will tend to flatten out slightly, so constantly check the stands position until the cars' full weight is safely supported. Check and check again that the car is properly and firmly supported. 

Remove the spring fixing access plate. Find a couple of bits of wood, about 2" x 2" x 3"  ( from memory) Then position these on top of the spring, directly next to the the outer edges of the spring clamp plate. You should be able to 'fiddle' these blocks into position either through the spring clamp access hole and/or reaching into the tunnel.  The idea is that the wood blocks should be a snug fit between the top leaf of the spring and the underside of the spring tunnel - to stop it moving up when you remove the spring clamp plate/nuts. Ensure that the blocks are firmly wedged in position. Then position the trolley jack under the diff to just take the weight, but no more, Do not allow it to jack the car off the axle stands. You can now remove the bolts/nuts from the halfshafts and rear propshaft flange. I found that I did not need to remove the exhaust pipe,but you might have to on a GT6. 

Now you can gradually loosen and remove the spring clamp nuts and clamp plate. Then using the double nut locking technique unscrew the studs from the top of the diff. You can cover the stud holes with masking tape to stop dirt ingress into the diff. Then remove the diff mounting front and rear nuts/bolts.The diff is now ready to come out, by gently lowering the trolley jack. As I was doing the job on my own I also tied the diff with some strong rope, onto the trolley jack cradle to stop it sliding about. Note that the rotoflex couplings will be pressing inwards against the halfshaft flanges, so you will need to gently lever them apart with a large screwdriver or pry bar, whilst lowering the diff out.

Replacing the diff is largely the reverse operation, but ensure that the spring centering blind hole on the diff case locates properly with the spring fixing 'peg' on the underside of the spring.Refit the diff mounting nuts/bolts.Then refit the diff studs and spring clamp plate. Remove the wood blocks. Refit the spring access plate. Replace prop and halfshaft bolts/nuts. Don't forget to torque up all bolts/nuts. Have a cup of tea.

Hi Gav,

Thanks for this detailed advice.

After a long hot summer and a couple of other projects I finally found some time and patience to swap the diff on my Vitesse this weekend.

In summary I followed your instructions word for word and it worked like a breeze, no spring lifters required, and no movement of the spring.

Called in a couple of favours and borrowed 2 additional trolley jacks (including a heavy weight one for the diff) just to add a bit of additional safety under the chassis, see photo. The larger lifting plate on the heavy weight trolley jack was ideal for holding the diff at the required angle when re-installing, in fact I got it spot on and it went straight in (more by luck than judgement !!)

To confirm, if you can remove it, removing the exhaust on a Vitesse certainly aids with access.

An additional tip I came up with was to strap a crow bar on the radius arm to lift the drive shafts up and away from the diff, giving me more room to drop and replace the unit.

Just need to tidy up the diff paint and take it for a test drive, had the cup of tea ;-)

Couple of photos below

Thanks to you and everyone for their advice and comments !!

Steve

IMG_8864.JPG

IMG_8867.JPG

IMG_8875.JPG

IMG_8889.JPG

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