Shock Absorbers and Diff(?) - Quote Shock

I took my 1990 model XJ40 with 448,000Km (280,000mi) into the local mechanics for some jobs beyond my equipment and confidence for working on the vehicle myself. I’ve been driving it as my only vehicle for nine years in which time it’s done 64,000Km (40,000mi) of country driving (very country - some rough Australian roads). I suspect that I got a bit of a “go away” quote.

Problems were:

  • Whirring noise from the rear end while at speed (I replaced the rear wheel bearings without any effect, and couldn’t find any play in the universal joints. I did notice cracks in the prop shaft flexible coupling)

  • Clunking noise from the front when going over big bumps.

They came back with the following major things that needed doing:

  • Replace all four shock absorbers (the back ones are annoying because they replaced them 50,000Km ago, but apparantly those are leaking as well as the front ones which caused the noise over bumps)

  • Replace rear wheel bearings (apparantly the noise was coming from the left rear wheel bearing, but as I’d already replaced that while chasing the same problem I’m doubtful that I could have stuffed things up the same way they they were before)

  • Wheel alignment

  • Four new tyres (rubber perished)

After a week of getting quotes they called me back with an alleged parts cost of $6,200. They suspiciously wouldn’t break this down for me, so given what good shock absorbers are advertised at online I’m pretty sure there’s a bit of a “go away” charge because they’re busy and said themselves that they don’t really want the job because it could tie up a hoist for weeks. They seem to think I should be willing to spend $10,000 - $15,000 on fixing those issues as well as other unknown issues likely to crop up while they do the work.

I do expect that other issues will pop up with the whirring noise, which I suspect is from the diff. The right output shaft bearing on the diff failed about five years ago, and they replaced it (for a much more reasonable sub-$2,000 fee including labour), but I noticed a new whirring noise as soon as I got it back. My opinion is that this same whirring noise has been gradually getting worse until now it’s quite uncomfortable at 100Km/h and I suspect it’s getting close to a failure of whatever it’s coming from. Maybe it’s from that bearing which was replaced, or it could be something that was affected when bits of the old bearing apparantly shattered, or it could be the output shaft bearing on the other side which is presumably due to go as well.

I’m not looking to get my money back on the thing down the track so around $6,000 total wouldn’t be out of the question. But for $10k - $15k I ought to be able to find a much lower km XJ40 with hopefully much more life in the diff (etc.)*. So is it worth chasing up other mechanics out of town, or would that be a waste of time? From what I hear there’s a shortage of trained mechanics here in Victoria, Australia at the moment so I might get a similar response anywhere. But if I’m living in dream land and that really is what it would cost to do a decent job (even myself, if I had the know-how), then I definately won’t bother.

*One’s advertised locally at the moment with 164,032Km (102,000mi) and claimed to be running well, but it’s unregistered so I’m highly suspicious.

Definitely a ‘go away’ quote. Let me just say I am in the USA, not Australia, but still…

Some quick online price checking leads me to believe that parts costs in the US (in US$) should be not more than:

Shock absorbers, $500
Rear wheel bearings with races, $150
Alignment, $150
Tires, all over the board, but say $700

The total is US$1,500, or about AU$2,250.

OmberJag …

If your differential is a “roar” that gets louder with speed and doesn’t change that much when letting off the throttle it is most likely the differential output shaft bearings. A bit of labor but parts not very expensive. As you know this job can be done without removing the differential …

If however it is more of a high pitched “whine” that comes and goes depending on you being off and on the throttle it’s within the differential itself. Try replacing the differential fluid and if that doesn’t fix the problem the differential has to be removed and rebuilt. A lot of labor, and parts cost depending on what you find.

Any time you hear a “clunk” going over a big bump the first thing that comes to mind is shock absorber bushings. The rear shocks on this car are notorious for this problem !!

It’s getting harder to find decent mechanics in the UK too. If you have a modern car that can be plugged into a computer to be diagnosed and repaired then you’re ok, but trying to find a mechanic who knows what he’s doing and who is prepared to tackle anything bigger than routine servicing / brakes, and exhausts is another story. That quote definitely sounds like a ’ I wouldn’t know where to start mate but I’m not admitting that to you so go away ’ kind of quote to me.
The cracked Jurid prop coupling should be replaced, anything rotating at high speed can emit a whirring sound and a cracked coupling falls into that category.

Thanks to all of you. Good to know I’m not forgetting something major with the parts cost, so it’s at least worth checking around some more.

The sound isn’t high pitched and definately gets louder with speed rather than throttle. It’s noticable above about 40Km/h, worrying/annoying above about 80km/h. It seems to be quieter when going down a steep hill though. It does also seem worse with a heavy load in the back, or with a full tank of fuel compared to nearly empty.

I think only one bloke at that mechanics actually does these sorts of jobs and he seems to spend all day at a desk answering calls, so I expect they don’t want it stuck in their workshop while he finds the time to do work on it. Whether anywhere else is better remains to be seen.

My main concern with doing the shock absorbers myself is compressing the coil springs because I never worked out where to get an appropriate tool for this. My research before I got the rear shock absorbers replaced last time suggested that the cheap spring compressor tools weren’t well suited. I probably could do the diff output bearing job (thanks for the video link!) if I borrow a press.

For the diff how about a replacement rear assembly?
That’s the way I went when I blew the diff on my XJR.

What’s a decent replacement car worth? The dearest XJ40 here in NZ is $6.5K and that’s way overpriced as it’s only a 2.9, but most of the 3.6 or 4.0 cars are 2.5-3.5K. Unless you are hugely sentimentally invested in this car, I think there are way better options than spending even $6k to fix some knocks and whines. As mentioned, shock bushes deteriorate and are a pretty simple DIY fix, and Robin’s suggestion of replacing the entire diff assy sounds sensible. All DIY.

I’ve got a parts car, a 1987 3.6L (the one I’m driving is a 4L). I’m not sure if the diff would be an easy transplant, 80% of the car seems to have been redesigned just enough to make sure that nothing from the old model quite fits. Which I’ve found out the hard way.

Thing is, it’s too big of a job for me. I don’t mind putting the time into doing it myself, but I don’t want to hurt myself and/or the car when I don’t know what I’m doing or even where to get things like the spring compressor for replacing the shocks. So I’ve been falling back on getting the big jobs done for me and lumping the cost, which was OK until now they no longer seem willing. I’ve found a mechanics that specialises in Jags and isn’t that far away, so I might try them next.

But I’m certainly considering getting another car. Ideally still an XJ40 because I know how they go together (the small stuff at least) and have the parts. Definately not a ten year old Toyota Camry like the mechanic suggests :). Tomorrow I’m going to take a look at that one I mentioned in the first post with just 164,032Km (102,000mi). Thing is, it’s advertised at $7,750, and sure to cost more getting it on the road. With me clocking up only about 7,000Km/year (7,400mi/year) though, it could last me a very long time if I can stop it rusting away (and assuming it hasn’t started already).

I’m not blind to the values. This current one cost me $2,750. But with 384,000Km (240,000mi) showing, broken air-conditioning, droopy headliner, worn-out driver’s seat, light rust, and an alternator that turned out to only have 300Km of life left in it (it stranded me on my first real trip!). My parts Jag has done under 300,000Km (188,000mi) and only cost me about $600 including delivery, but it had rust bubbles on the body and water in the oil.

I’d rather start again with one that’s not quite so worn out, if it comes to that, so I’m looking at the higher end for replacement cost. But really I’d prefer not to give up on it for less than the $6k. I’m a slow worker and I’ve spent a lot of time on it doing the more rare repair/replacement jobs I could do myself (fuel pump, starter motor, driver’s seat, both A/C blower motors, exhaust manifold resurfacing…), which might need doing again on another one. I’m at my limit with the diff and shocks DIY-wise though, I can’t even be sure the mechanic isn’t right about me stuffing up replacing the rear wheel bearings - the only other time I’ve done it was replacing the front ones after I got the car.

In my experience, front shocks are easy and don’t require much time - the heaviest part of the job is removing and remounting the wheels. The rears are not too bad and good spring compressors are easily sourced for not too much money.
On my car (94MY), if you use the spring compressor method, they have to be fitted BEFORE removing the rear shocks, but on yours, you take the shocks out and do the spring removal on the bench.
If you jack up the rear and remove the three bolts under the rear end the suspension drops enough so that it’s easy to pull the shocks which are held in by 4 nuts up top and a bolt below. Basically the job involves removing the rear wheels, un-mounting the still-connected caliper and tying it up out of the way.

Certainly an easier job than doing blowers or starter motor etc.

BTW I’m no spring chicken, 75 next birthday. :roll_eyes:

Thanks. The main thing that puts me off the job is that the Haynes manual explicitly says that you need a JD115 spring compressor tool to do the front shocks, and that a MacPherson strut spring compressor isn’t strong enough to safely compress the rear springs.

I’ve looked through YouTube and the Jag Lovers photo gallery (back when it still worked properly) and never found any detailed guide to doing the job on the XJ40. Without any experience myself, I’m unwilling to outright contradict the manual without some very specific alternative instructions+photos.

I’m 28, so still just about flexible enough to do that A/C blower motor job (though there was a lot of swearing!), but I’m not much good experience-wise.

Not imperative to have the Jaguar tool for the front springs, this has been used on ‘66 Stype, XJ40 and ‘99 XJR

You don’t touch the front springs if you replace the front shocks. They are totally independent of the shock assemblies.

Here’s the pics of doing the rears. Not a big deal.

It is correct the regular spring compressors are nowhere near strong enough to compress the front springs BUT as Larry pointed out you don’t need to touch them to change the front shocks, they simply unbolt from the car leaving the springs in place. The rear shocks are not very difficult to remove as a complete assembly and a good pair of regular Mc Pherson type spring compressors can be used to dismantle them once off the car. You will definitely need to replace ALL the rubber bushes and foam doughnuts including the little ‘cowboy hat’ shaped red ones when you do the job. I would look at the exploded diagram and buy all the bushes shown for both sides before you start. Also spray the four mounting bolts each side that hold the shock assembly to the floor of the car liberally with penetrating spray for a couple of days before you start, they can be quite tight and you definitely don’t want to shear one of those, use a quality socket to ensure you don’t round the heads off, and when replacing them be very careful not to cross thread those bolts.

1 Like

That’s excellent! I’ve been jumping to some completely wrong conclusions. Looks like I could get the front ones done in much less time than today’s trip to look at that other Jag for sale (excellent body and leather, but lots of minor to moderate mechanical faults and an unknown service history). The rear ones look very approachable now too.

Tomorrow I’ll start working out the parts to order for all the shocks, the jurid coupling, and probably the diff output shaft bearing.

Thanks everyone!

Where are you in Victoria? I’m in SW Vic (Penshurst) and I’ve done all those jobs. In fact, I just replaced the Jurid. I’ve got all the tools (spring compressor, hydraulic press) and a lift. I’m happy to help if required.

1 Like

Thanks for that great offer. I’m at a place called Ombersley (roughly between Winchelsea and Colac). Perhaps a little far away so I’ll see how I go on my own, but I’ll keep it in mind.

I’m keen to hear any suggestions for Aussie parts suppliers. So far I’ve delt with mainly Prestige Spares, but also JagDaim who sell on Ebay and Preston Paige Classics. Only Prestige Spares seem to list all the parts I’m looking for now, so I’ll get a quote from them. JagDaim have some, but they’re usually expensive. Preston Paige only have the front shocker bushings (at half JagDaim’s price).

Anywhere else I should check with? I might check out overseas Jag parts websites because it could be worth the postage cost for this.

I haven’t had much luck getting decent pricing from general car parts suppliers in the past, so I don’t normally bother with them.

Try Rockauto on the states or SNG Barrett.

It may be worth joining the NZ Daimler Lanchester Owner’s Club. They also allow Jags in, and have associate membership for O\seas members and have good supply of maintenance parts for the newer models now, at competetive prices. I know, in the past, there have been many Aussie members, and shipping from NZ is probably cheaper than UK or US or Europe. Memberships subscription is reasonable, and probably recouped on your first purchase. Find them here

Thanks, that gives me some more options.

1 Like

Just want to give a shout to Jagdaim. I don’t know if they’re more expensive but the service is excellent.
If they don’t have it, which is rare, they get it smartly. I bought quite a bit when I was getting my S2 XJ12 going. And when there was a problem ( apparently it’s a change over model) it was fixed rapidly.
I tried to get onto one of those you mentioned, regarding some wheels, and the phone number on their website isn’t connected. The other one you mentioned is on a break.
No affiliation, just a happy customer.

1 Like