Diff cage refurb

An Integrale rear differential support cage is important, it's a pressed steel item and being located under the car it is subject

to corrosion. The cage needs looking after, but it's a bugger to remove. Let's see how Barry did his.

The diff cage hangs under the Delta's rear end and supports the heavy differential. It also supports the suspension tie rods, brake limiter arm and a few other things too.

So the cage needs to be looked after, this means removal, which is a daunting operation.

We know of several Delta owners who are undertaking this operation at present, Barry has just done it and he'll talk us through the job.

Days, or weeks, before you start this job, soak the nuts and bolts in penetrating oil a good few times. As Barry says these components might not have moved for 30 years, the long lower hub bolts can be tight and if they shear off it's difficult to get them out. Gently persuade the bolts, loosening and tightening, break their locked grip. I have used a strong bar and easily sheared the bolts before now, a powerful impact gun can also cause damage. New bolts are available.

The job, as Barry did, can be done with the fuel tank in place, if you're fitting new tank straps at the same time, drop the tank then

disconnect the prop shaft.

The problem is accessing the top 17mm nut fixing the torque tube to the diff, the lower nuts can be reached with a long extension. If you can get all those nuts off, you can undo the prop shaft support and the front cage, then lower the shaft on a jack, while withdrawing the tube from the diff. If you can't do it this way, the fuel tank can be lowered.

I'm going to hand over to Barry who'll talk us through it...

As for removing, and as with all things integrale, freeing nuts and bolts that have never moved since they came out of Turin 30 plus years ago can be difficult, but as in most cases I had been there before that really wasn’t an issue. An impact gun would be helpful though, especially for the 2 large bolts that hang the cage from the car.

Obviously removal of all components fixed to the cage is essential first. I started by removal of the hubs and driveshafts, then the adjustable arms. Also, but not absolutely necessary I removed the brake bias and pipes. All leaving a bare cage only coupled to the running gear by the torque tube. I actually managed to pull this off the diff without dropping the tank, but only because I had had the prop off before.

Then it’s over to very securely balancing a trolly jack under the diff on a block of wood and windy gun the 2 large bolts off. Best to have an assistant on this part as it is not

centrally weighted.

After that once it’s on the floor just undo the carrier bolts that are only accessible once it’s off.

And there you are. It’s off!

As they say refitting is reverse procedure, it took me about 3 hours to remove and about 6 to put it all back.

While in bits everything was re-tapped and threaded to ensure as easy a refit as possible.

Once the carrier was back from powder coating I liberally coated all the inside and welds with wax oil and as you can see repainted all the arms etc.

Diff cage removed, Barry scraped all the loose paint off and inspected the cage, before taking to the blaster's.

Blasted.

Showing the inside, which has plenty of traps for corrosion.

The finished cage, blasted, primed and powder coated. This is now a lovely and protected object.

Have a look below at Barry's underside, the alloy finishing is done gently and doesn't harm the soft surface.

He degreased everything, then wire brushed the alloy, this gave a good key for a light coat of Plasticote.

After carefully masking everything up Barry gave the parts a light dusting with Plasticote aluminium paint.

Light enough not to form a glossy skin, but enough to give an authentic protective finish.

Thank you Barry, we look forward to your next project.

Barry gave all the suspension components a very good rubbing down and a repaint at home. Below is his Delta's rear suspension completed and reassembled.

 

I've commented before on Barry's standard of workmanship, it's something we should aspire too. Our little Deltas deserve the best treatment we can give them, they won't be making any more!