Drivers Diaries

More workshop updates from our regular contributors.

The past few weeks have been mostly about working on my son David’s Jeep Grand Cherokee. It’s a great car, which I liken to being the automotive equivalent of a hammer – there’s nothing too pretentious about it, it’s just a tough old beast that does a great job of work. However, being tough doesn’t mean that things don’t wear out. With the MoT looming, David and I felt that it would be sensible to have a good look at the Jeep and see if there was anything that needed doing first.

To be honest, for some time now the Jeep’s rear end has been a lot less stable than it should be, which suggested to us that a worn rear suspension was likely to be the culprit. Upon investigation, we found that the upper suspension control arm (which is shaped like a boomerang) was not only very rusty, but its central balljoint – a beefy affair that bolts to the top of the rear differential – was exhibiting significant wear. A new control arm was ordered, together with a balljoint, and we set about fitting them.

Well, we tried to fit them! To say that the old arm refused to budge from the balljoint is an understatement as rust seemed to have welded the two together! We jacked the arm up, we levered it, we hit it with a mallet, then, many hours later, we gave up for a while. The problem is that the arm is tucked high up. Worse still, the balljoint pretty much covers the three large bolts that secure it to the differential. The arm can only be removed by pulling it up and over the balljoint.

In desperation, having tried every tool in my armoury, I borrowed a rather beefy balljoint splitter from my good friend James Stark, plus a long metal bar, and we tried again. Eureka! By inserting the splitter and getting the angle correct with the use of steel packers, then belting the splitter with a mallet, the arm eventually relinquished its grip on the balljoint.

Thankfully, fitting the replacement was much more straightforward. Having done this, we then fitted new rear drop-links and anti-roll bar bushes. The anti-roll bar bushes should have been a quick job, but of course things rarely work out quite as they should on old cars. In this case, it was because someone had previously fitted a wrong-sized bolt in one of the mountings, and this bolt snapped as it was being removed. I then had to spend quite some time drilling it out to allow for the fitting of a new bolt and nut. The good news is that after fitting the upper control arm and the drop links and bushes, David reported that the Jeep drove in a much more stable fashion than before.

Nothing lasts forever though, and a few days after doing this work, David

rang to say that the Jeep was weaving under braking and acceleration. Puzzled, we took it down to the barn and did some investigations. What we discovered was that the nearside lower arm had developed a significant amount of play, and the cause of this play was one of the bushes parting company with the arm. So we removed both lower arms, ordered replacements plus new bolts, and fitted these items two days later. Thankfully this was a straightforward job, although we did have to use a ratchet strap to tension the axle in order to align the bolt holes.

Anyhow, the Jeep now drives very well indeed. In fact, David reports that it drives the best it ever has in his ownership. As for why the bush tore free, I can only assume that the new upper control arm and new anti-roll bar bushes placed the 20-year- old lower arm bushes under enormous loadings. Whatever the reason, the rear of the Jeep is now tighter than a tight thing!

Elsewhere, the Porsche 944 Turbo sailed through its MoT with no advisories, which pleased me greatly. It’s a very nice car to drive, and it’s been behaving well too, although there are a few jobs on my ‘to do’ list, the oil filter heat shield being one of them. It was bought new from Porsche about 18 months ago, but it fractured some time back. Unfortunately, it’s an absolute nightmare to access. Plus, even if I do replace the shield, it seems as if there’s a basic design fault which means that it is likely to fracture again. As a temporary fix I carefully drilled a hole in the shield and bolted a perforated steel strip to it. I then attached the other end of the strip to a bracket on the head, and this held the shield in place and away from the filter. However, a permanent solution is required, so I need to do some more thinking.

In the meantime, a few weeks ago I noticed that the pipe connecting the battery vent to a small canister tucked away to the rear of the Porsche’s battery had broken. I bought a replacement and fitted this – I wish all jobs were that simple!

And finally, the Davrian has been sitting idle, so I started the engine and drove it in and out of the barn so as to ensure that everything is freemoving. I’m planning to fit new driveshaft bolts, although I must say that is a job I’m not looking forward to.

“I can only assume the new upper control arm and anti-roll bar bushes placed the 20-year-old lower arm bushes under enormous loadings”

ABOVE: The new upper control arm and balljoint in situ.

ABOVE: David (who is wearing safety goggles!) grinds the heads off the bolts holding the brackets that secure the handbrake cables. They need these for the new control arm (pictured).

ABOVE: Another year, another MoT for the Porsche! Mind you, due to the pandemic through most of 2020, the Porsche had only done 1234 miles since the previous test.

ABOVE: Fitting the lower control arms was straightforward, although to get the bolt holes to line up Martyn and David had to use a ratchet strap to tension the rear axle.

ABOVE: On the Porsche 944 Turbo there’s a small canister behind the battery that catches any vented battery gas. The connecting pipe had broken, so Martyn fitted a new one.

ABOVE: Like the upper control arm, the lower control arms weren’t in a very good state, and one bush had made a bid for freedom. Replacing them was essential.