Differential Washer / Bush ?

[Apothecary]

Having recently topped up the diff oil on my LA car I noticed that the (rubber?) washer/ spacer used where the lower casing of the diff is bolted to the frame has disintegrated.

 

Can anyone advise exactly what I need to replace this

Is it just a spacer or more intricate (perhaps a bush) and what size do I need ?

 

I assume this isn't the cause of the increased drive shunt I'm experiencing (1300 miles) but its obviously supposed to be there so I'm keen to replace.

Any advice most welcome, Thanks.

 

Paul

[Dave H]

This sounds like the rear A frame bush - they don't last very long on the Live Axle, especially if you get any oil on them.

It's a 30 minute job to fit new ones, you need a pair of them. They are top hat shaped and you push one in from each side. Caterham & Redline both stock them and supply mail order - I usually buy half a dozen or 10 at a time.

It is more than likely to be the extra drive train shunt you're getting.

 

Dave H

[Apothecary]

Many thanks Dave, think your diagnosis is spot on

 

Any tips on the procedure for replacement ?

 

Paul

[Graeme Smith]

My proceedure:

 

You’ll need:

· Trolley jack

· Two axle stands

· 19mm (?) spanner and socket

· Big screwdriver

· Really big set of water pump pliers - something like http://buy.snapon.com/catalog/pro_det.asp?tool=hand&item%5FID=6890&group%5FID=753&group%5Fname=Tongue+and+Groove%2C+chrome&sub%5Fcat%5FID=1461151&sub%5Fcat%5Fname=Adjustable+Joint&cat%5FID=1461107&cat%5Fname=Pliers&store=snapon%2Dstore&dir=catalog

 

Technique

· Jack up the car from the A-frame bush (probably not technically the best point, but handy)

· Put axle stands under the rear chassis rail - one each side

· Undo the nut and bolt holding the A-frame bush - a spanner and ratchet socket/spanner are handy

· Free the A-frame from the axle by levering it down with a big screwdriver - the bushes will pop out

· Remove the bushes and insert new ones

· Squeeze the bushes in with the big water pump pliers (adjust the jaws so the you can comfortably hold them closed with one hand) and slide back into A-frame casing on diff - you just need to get the edges in

· Hammer the bushes/bush carrier roughly into position - the back of the water pump pliers are great for this! Use the big screwdriver if necessary to line up the hole.

· Put the bolt through and hammer it home with the back of the pliers again - the hole in the bushes is tapered, so the bolt will find its way

· Do up the nut and bolt and lower the car

 

[kirium]

Having replaced my A-Frame bush a fews times... here's the best tip - Prepare to swear continualy whilst doing this horrid job 😬

 

I have recently been told, that the best way to do this is by using a strong pair of grippers. You probably need a pair with longish handles so enough leverage can be achieved. Basically you need to grip the suckers together whilst gently easing the A-Frame assuembly back together - having a trolly-jack under the diff casing may help you - it's not too easy trying to support the whole diff assemble in one hand whilst gripping the bushes and aligning them together..

 

I wish you good luck...

 

 

[Dave H]

Once I've jacked the car up, and got it on the axle stands, I put the jack under the front of the diff, take the bolt out and then use a lever (big screwdriver) to move the Aframe enough to get the bushes out. If you don't support the front of the diff the axle will roll once the Aframe is free, and it makes refitting even more of a pain.

 

You can use the a nut and bolt to compress the bushes enough to start fitting them, then remove the bolt, press/hammer/force the Aframe back into position, then insert the original bolt.

 

Do not try this job while anyone of a sensitive nature is around...you may even remember some words you thought you'd forgotten 😳

 

Good luck,

Dave H

[Graeme Smith]

Dave,

Are you putting the axle stands under the axle - if so, this sounds why you're having problems. If you put the stands under the chassis everything lines up fine and its a rather plesant 5-minute job.

[Dave H]

Graeme,

Under the chassis, I've always found the axle rolls forward once the Aframe is disconnected. I agree if you put the stands under the axle the job becomes even worse, and the axle & Aframe become complete b******ds to line up.

A pleasant 5 minute job 🤔 - not on my car it ain't. Never been one of my favourite jobs.

 

Dave H

[bstark]

Took an expert from Arrowstar 10 minutes to do my car at a trackday recently - having watched carefully, here's the procedure:

 

Jack car up at rear, support on rear chassis rails with stands.

Remove A-Frame diff mount bolt (may require a hammer and centre punch!).

Loosen the other two A-Frame mounts, enabling you to pull down the frame at the diff end and remove the old knackered bushes.

Clean everything up!

 

Fit new bushes in A-Frame, then carefully re-insert into diff mount (this is a very tight fit, and the bushes need to be compressed as close to the top as you can to avoid damaging them on the way in (adjustable pliers were used) - this was the most fiddly bit! Once a sensible way in, a hammer can be used to gently knock the A-Frame back into position, then use a long screwdriver or simliar to align the holes up, before re-inserting the bolt (this was surprisingly easy).

 

Now the tip - Do the bolt up so it is effectively finger tight (I know its a nyloc but you know what I mean), then jack the car up off the stands under the A-Frame mount to get the axle to normal ride height. Now fully tighten up all three mounting points - the reason for this is so the bushes aren't under constant strain when the car is just sitting there (which would be the case if tightened with the axle at full stretch).

 

Lower car and away you go

 

Bob Stark

Supersprinter

 

Edited by - bstark on 29 Aug 2003 12:55:18

[Nigel Riches]

.........and fix the diff oil leak, unless you want to be doing this again in 1300 miles, or fit a Rose joint "A" frame, no more nasty rubber bushes........Nigel.

 

1982. 5 speed, clamshells. B.R.G / Ali. The True Colours.

[Apothecary]

Thought I would update everyone after having completed this job this morning

 

Having spoken to John Payne at Redline he suggested a procedure that I thought I would try before having to go out and buy axle stands etc. It took me about 20 mins in the end so might be worth a try for all those who hate doing this/ cannot raise the car onto stands at the time. You just have to get down & dirty.

 

1. Chock the front wheels to stop the car moving forward & apply the hand brake.

2. Undo the nut & bolt

3. Prize down the A frame ( I used a long handled screw driver to pivot against the chassis) & remove the old bushes.

4. Clean it all up

5. Lubricate the new bushes (washing up liquid) and place in the A frame mount.

6. Squeeze into place at the top edge using water pump pliers and move the A frame back up to meet the Diff. This requires a bit of effort but as others said you do only need the leading edge to locate into place.

7. Now place the jack under the A frame mount and carefully raise so that it simply pushes the A frame back up into position.

As the car is not of the ground the axle / A frame alignment is exactly as it was when it was undone. Remember the car cannot role forward either as its chocked 😬

8. Simply align the holes using the screw driver & knock the bolt back into place & tighten.

 

Using this procedure you could even do it when out on a blat if necessary!

 

I'm surprised at what a significant difference this has made to the ride. No more drive train shunt, no clonking over pot holes etc

 

Again, thanks for all the contributions on this thread.

 

Paul 😬

[Ferrino]

I followed Paul's advice on replacing the bushes without lifting the back of the car and found that this worked a treat .

 

I couldn't believe how destroyed the bushes were (first time I have replaced them since purchase in June). Part of the rubber from one half was actually hanging out of the A-frame. I didn't find it too tricky to lift the bushes into the diff - lining up the holes took longer.

 

Cheers!

[Nov-07]

This A-Frame topic is making me think that before I lower my new-built SV onto its wheels I should loosen the A-frame mountings so that they can be torqued up when the suspension is in its "normal" position. The build manual tells you to do this with the front suspension fixings, so why not at the rear also?

Beware of using washing-up liquid as a rubber lubricant. It may be full of salt which will not do the metal bits any good. Ordinary soap would be OK.

 

 

TonyK

[Asklepios]

Tony makes a good point about washing up liquid. I would always use proper rubber lube.