Plain sailing
The leaky Salisbury 3HU differential receives new seals
The polished P grille I mentioned last month as being my (fictional) bringer of bad luck has, I hope, done its worst. The new head gasket is holding well and the engine is running better than ever again. So much so that I came within four wheels of having the car being driveable. Almost.
Polishing the P grille was no small task, and I spent close to three hours rubbing it down with ever finer grades of wet and dry paper before using polishing compounds and a high-speed bench-mounted polishing wheel. The aluminium grille was the first one cast using the new mould and was the roughest New Pro ever made for owners. Although they can polish metals to a superb standard, I naively chose to polish my own. The finished result is a combination of shine and careworn casting marks, creating a patina I hadn’t intended but suits the ethos of the restoration.
With the engine running and propshaft connected, I had tentatively put the car in first gear and fed power through to the rear wheel hubs. With the car off the ground and the rear seat tub removed I could easily see the rotating rear brake drums. I could also hear the clunk of a tired UJ, or so I thought. The obvious weeping of gear oil from the diff casing was enough to have me remove it with a view to at least replacing the seals and gaskets. First, the sliding driveshafts were unbolted and at once I discovered the sliding splines of the nearside shaft were worn and making the clonking noise I’d heard. The UJS weren’t noisy but they were sloppy, justifying their replacement. The offside driveshaft appeared okay, though that diagnosis was shortlived once the expert hands of Nigel at HJ Chard in Bristol inspected them and the propshaft a few days later. Originally, the driveshafts were made from cut down TR3 items and the sliding joints identical to the splines you find on a sliding propshaft joint. I left the driveshafts with Nigel and went home to count the pennies in my piggybank and down the back of the sofa while I awaited his call, like an expectant father to be.
Diff carrier bushes
To remove the Salisbury 3HU diff, I simply unbolted the eight bolts securing it top and bottom to the space-frame chassis mounts and lifted it clear of the chassis and up through the car. The lower bolts secure to a triangular carrier which is then bolted to the chassis via three Metalastik-type rubber bushes. A single bush sits atop, pivoting. PWOR members had discovered the bushes are also used on Jag Mk2s and a few other cars of the era, so a quick check with David Manners confirmed they are readily available. I removed the carrier and secured it in a bench vice while I carefully drilled out the rubber and also just enough of the outer steel casing to
weaken it sufficiently. Two drill holes 10mm apart in this manner meant that once the remaining rubber has been drilled out, the weakened strip of metal can be chased out with a drift and the bush simply knocked out. New bushes were pressed in with the vice and the cradle painted.
New seals and bearings
The diff seals and gaskets proved more difficult. I discovered that new gaskets for Salisbury 3HA and 3HU casings are not available, so using gasket paper, hole punches and a cutting protractor, I made my own. The rear cover seal was saved and cleaned up well enough to be reused, albeit with the help of Wellseal gasket sealant, too. Removing the tired, old leather output shaft seals and pinion seal required the use of a puller for the pinion flange and some initial head scratching for the output shafts’ removal. Once I figured out that only more force was required, both output shafts were soon on the bench complete with their outer bearings, shims and the failed seals. The output shafts were then pressed out through their bearings, having removed the circlips and spacers first. The seal housing then becomes free and the seal can be pressed or punched out. I managed to source new double lip seals for the output shafts locally and the pinion seal is to be replaced with an improved version approved by the Daimler Owners Club for SP250S. The old bearings were discarded just because it made no sense keeping them when new quality Koyo replacements are readily available. While I waited for the new bearings to arrive, I cleaned up the casing and painted it with Rustbuster 121 Epoxy Mastic paint. Although I’m so close to being able to drive the car for the first time ever, I know that sorting these critical items first will ensure I avoid even bigger problems if ignored.
‘The familiar clunk of a tired UJ was unmistakeable’