Welding a Brumby rear diff

Jack · Post by **Jack** » Sat Apr 22, 2006 2:49 pm

I'm having difficulty finding a secondhand clutch LSD for my rear diff and new ones are priced at $990 each, which is a little too expensive for my wallet. So I'm wondering what the pro's and con's are with welding the rear diff?

I use my Brumby as a daily driver and go offroad every second weekend. When offroad, I'm finding the open diffs are a real hindrance that's why I want to improve rear wheel traction.

What do you think I should do?

tim_81coupe · Post by **tim_81coupe** » Sat Apr 22, 2006 3:31 pm

Basically what most welded diff owners do is run one axle on the road and two off the road. To do this we basically cut the LH diff stub about 5mm shorter to facilitate easier removal and installation of the axle, and all three of the stubs I have broken in my wagon have been RH stubs...

On the road you drive around with one axle in, granted it really is only a 3WD then, but when turning a corner or say, pulling into a servo to fill up your rear tyres won't be having a squeaky conversation with each other. That and people won't compare your Brumby to a Gemini.

When you go off the road you'll need to put your second axle in. You'll need to jack up the LH side to line up splines by spinning the wheel, and you'll need one CV pin on the diff side (never needed to run one on the wheel side) Jonno from WA keeps a CV pin slightly tapped into his axle ready to pop in at any time. My method is a little more mad, I basically slide a 6mm split pin in by hand and bend it over. However you want to do it is the best way, but remember time is of the essence

Yes it does take a little longer to do than locking a set of freewheeling hubs. So if you do go 4WDing with "real" 4WDs, you may want to pop the axle in before you leave home. Driving with both axles in on the road causes the car to understeer a little more everywhere and causes the axles / stubs to stress and eventually break under low speed cornering.

Off the road the diff is a revelation. Much better than any LSD, doesn't matter if a wheel is in the air or what, you'll always have rear drive. I've watched both viscous and clutch pack LSD's slip like crazy off the road, and it makes me glad I for the onroad sacrafice.

Definitely cheaper in the short term too, although I would recommend getting a pair of rear axles as spares just in case.

stinky · Post by **stinky** » Sat Apr 22, 2006 3:59 pm

^^ what he said.

Also try and get a stub axel tool ( e10 torx ) and a few spare stub axels

AndrewT · Post by **AndrewT** » Sun Apr 23, 2006 7:29 pm

Doesn't really matter if its a 3wd on the road - I'm guessing its a normal EA81 or EA82 dual range gearbox which means you'd just be running in front wheel drive on the road anyways.

I agree this is the best bang for your buck by far. Better offroad than any LSD and as Tim says, doesn't really take much longer to engage than some free-wheeling hubs on a "real" four wheel drive.

vidler · Post by **vidler** » Sun Apr 23, 2006 8:26 pm

ill back tim up to but i'd lake to add that if you make the right hand side the removable axle, you dont need to trim anything off anything... i originally have the left side one removable and i had to cut about 5mm off the diff stub and about 3mm off the cv cup to get it to slip on and off without to much hassles. i later found out that the drivers side will do this no modifications and a hell of a lot easier.

but before you take a grinder to anything, try both sides 2 see which is easier.

tim_81coupe · Post by **tim_81coupe** » Sun Apr 23, 2006 10:08 pm

Andrew I said it does take a bit longer than locking hubs. All it takes to lock a hub is for the vehicle to be parked straight and for someone to quickly turn the hub lock mechanism on each side, takes all of 30 seconds.

As for an axle, well best time of mine would be 2 minutes (including getting the jack out of the car).

AndrewT · Post by **AndrewT** » Mon Apr 24, 2006 11:15 am

Yep, 2 minutes compaired to 30 seconds = not that much longer.