Winter Job 1 - Differential (Advice Needed)

[Norman Verona]

Remove prop, undo the ring of bolts in the axle casing, remove the half shafts and the diff will come out.

Phil at R&R will tell you the ratio and they will rebuild the diff. Phil is the best man for gearboxes and diffs, he must be because he tells me so every time I go there.

The other option is to take it to Brian at BGH.

[Norman Verona]

Oh, forget to answer your other question.

Diff ratios. It's entirely up to you. a low ratio will give you quicker acceleration but high revs on high speed trips (motorway or some tracks). High ratios will give you lower revs for high speeds but slower acceleration.

If all you do is blat around country lanes go for a low (4.44?) for maximum acceleration. If you journey on motorways then go for a 3.62?

(I've put question marks against the ratios as I'm not sure what's available for an English axle)

[Young Pretender]

Thanks for the info Norman, that's been very helpful. I've got as far as removing the prop and undoing the bolts (or loosening at least) on the axle casing. I thought it best to stop there on the basis that my neighbour pointed out that the drive shafts would need to be pulled out first. You have confirmed this above so glad I didn't just go ahead and try to rip the guts out!

I'm guessing that removing these drive shafts is not going to be that easy. Anyone who can give me any pointers here, your thoughts would be welcomed. Am I better off getting the whole axle out first? Think I'll do wheel bearings whilst I'm at it.

Nice to hear another endorsement for R&R. I have every intention of going there.

[Terry Everall]

You may well be very limited regarding ratios for your diff

[Young Pretender]

Sorry, what do you mean Terry?

I had two full turns of the prop to nearly one full turn of a wheel. Think that put's my diff ratio at something like approx 2.1 which sounds a very high ratio? I may be completely misunderstanding here. Will try and find a good source to read up.

I want the car to be at it's best on track therefore, I guess, a healthy balance between acceleration and top speed, not interested in motorways. But I guess it's not as simple as what diff ratio do you use? i.e wheels sizes and gearbox ratios come into play as well. This has the potential to hurt my head.

[Dodgey]

Pulling out the half shafts is dead easy.

Remove wheels

Remove brake drum cover

Remove brake shoes - - I took a photo so I could put them back right. All very easy.

There are 4 bolts behind - undo them

Now pull the whole assembly (obvious when you look at it) and the half shafts, along with the square plate at the back of the brake drum (that you removed 4 bolts from) will pull out. You might need to bash with a rubber mallet.

You only need to pull them out around 6 inches but you can't do any harm pulling more. The shafts will come out with their wheel bearings in place.

You will also have to disconnect the horizontal suspension arms and one shock absorber bolt from one side to allow the whole axle to push back a bit - this gives you room to get the diff out as it is going to have to come forward before it will drop out as the gears live inside the axle housing. From memory I disconnected both horizontal bars on both sides and then one shock absorber on one side, this allowed plenty of movement of the whole axle.

Now the diff will come out. (clearly you have to undo the drive shaft flange bolts 1st)

I undid the diff casing bolts leaving the top one in place till last, then let it drop into a large baking tray (there will be a lot of oil - I recommend loosening all bolts until oil starts leaking, then leave it a while to drain)

Your ratio is simple to work out once the diff is out. Count the teeth on the small pinion gear at the bottom, and the teeth on the large crown wheel - and that is your ratio. - You them make it more usable by dividing the big number by the small one. eg 9 teeth pinion and 32 teeth crown = 32:9 or (32 divided by 9 = 3.55) 3.55:1

pm me and I'll give you my phone number and you can call me if you want to run through anything. I was new to all this and it's actually rather simple. The trick, for me, was to make sure I have a way of handling the oil spillage, and having good axle stands so I was happy being under the car (I also put the rear wheels under as a backup). The rest is just a matter of taking your time and taking it one bolt at a time :-)

p.s. I have a 16v 1600 engine that revs to 8.5k and I had a 3.77 diff which was wrong for my car. I now have a 3.89 which is much better

The ebayer I bought my diff off promised to refund me if it was a bad diff but he seemed confident it was ok and clearly knew what he was talking about. There is of course a risk, but I decided it was worth a punt as a recon was looking to be around £600. I figured that I could "try" 5 diffs from ebay for that :-)

[Young Pretender]

Fantastic write up, thanks for taking the time to do that. I will certainly pm you if I get a bit stuck

[Dodgey]

Here's a few photos I still have:

Suspension bolts undone so the axle housing will go back enough for the diff to rotate and drop out.

Below: If you look through the top hole in the nearest part - the disc with the studs in it, you can see a bolt behind it - that is one of the 4 you need to undo. You can put a socket through the hole so I dont' think you need to remove the brake shoes at all. Those 4 bolts are what hold the whole brake assembly to the axle.

To give you an idea what you are working with - below are the shafts removed. The studs you see at the bottom are the wheel studs. Just below the bearing you can see a small square plate - that's the thing you are unbolting as per above. Clearly I've removed the brakes in this instance but I don't think you need to.

[Burlers]

I didn't have to remove the brakes to get the half shafts out. A shaft puller makes it sooo easy too

No one's mentioned mind bending drugs yet, and i dont want to create massive thread warp but have you thought about whether you're gonna want an LSD? This will put your price up big stylee but it might br worth thinking about now if you're going to be track focused??

Good luck

[Young Pretender]

Dodgey, cheers pal

Did you manage to remove the shafts in a single garage? I'm wondering about the room I have to get them out. If you got them out as your car stands in that pic then I may just make it!

Burlers, haven't really felt the need for lsd tbh, although I considered it until I saw the price

[Dodgey]

I hit the hub a few times around the edges with a rubber mallet and the axles just fell out. Just needed to "shock" the splines loose it seemed.

I was about to buy a slide but Mr Mallet, as always, shone through :-)

Yes they came out in that tiny garage as the car was on those stands ! :-) - though as you now know, you only need to pull them out 6 inches or so anyhow to get the diff free. I removed mine as I changed my wheel bearings at the same time as one was p1ssing oil through it's seal.

I fancied a LSD too until I saw the prices. Saying that, on the track it's not been an issue. I'm hill climbing next year and that's when I'm going to wish I had one.

[Young Pretender]

Interesting, I also have a wheel bearing that's leaking. Manage to get it off the shaft and replace it yourself or did you have to take them somewhere? A chap I know who has some experience with english axles says they're a right pain to get on/off. Or is a rubber mallet all I need

[Dodgey]

I took my bearings off - I used an angle grinder with a cutting disc. It's easy enough but you do need the grinder.

As for putting the new ones on, I paid a garage to press them on and then spot weld the collars that they come with. I have neither a press nor any welding kit.

It is worth cutting them off yourself if you don't know/trust your garage well. I actually cut just one off, and as it was so easy, I left the other on for the garage to do. As they were already doing the rest of the work, and they have access to a smaller (better) air driven cutting wheel it should have taken them a few minutes to cut it off, instead of my 15 mins or so. Didn't work out that way. When I got the bill for 2 hours labour I asked how it took so long and the reply was , "took ages to get the bearing off mate - was a right pain of a job". B0ll0cks! - takes no time with a cutter. You live and learn :-)

It's all detailed in a post / thread of mine on here.

This also might help :

http://forum.wscc.co.uk/forum/index.php?/topic/97032-how-do-you-push-english-half-shaft-back-in-bearing-rubber-o-ring-is-stopping-me/page__fromsearch__1

[Young Pretender]

Hey folks, struggling with a few things this afternoon..

1. Can't remove one of the rear brake hubs. hit it very hard lots of times with both rubber and metal mallets! Can't try one of the two bolt holes through the centre of the hub (I think they are there to tighten bolts in order to prize off the hub) because the thread has rusted. Tried using a screw driver to prize it off but doesn't want to give. Feels like it might but can't seem to get enough leverage.

Feels a bit like the brake shoes might still be gripping maybe? It's the hub which has suffered oil leakage. Any tips?

2. On the other side I have removed the hub and the 4 bolts holding the drive shaft to the axle. I have tried striking the drive shaft in the centre very hard with a metal mallet (through a large socket) however it doesn't budge. Any one have any old school methods to get it out without me having to purchase a puller ?

[Young Pretender]

Managed to get the driveshaft lose now. Used a phillips screwdriver through the vacated axle bolt hole, outwards towards driveshaft and hit it a few times with a mallet. What should happen with the rear of the brake hub now? Seems to be preventing the removal of the shaft.