Heyas,

I got my '93 4.0 convertible into a britshop this week, and received an assessment of my suspension this morning. With the exception of the steering bushings, which were recently replaced with poly, the whole thing, front and back, needs eventual replacing. The good news is it doesn't have to be done all at once. Given some time and intestinal fortitude, I may even attempt to do some of the work myself. At the moment, though, I simply don't have the time, space, or tools to attempt this sort of work. So the shop gets the first stab at this.

• Upper control arm bushings are kaput; this had noticeable effects on road handling vs bad pavement. This issue has shot to the top of the overall priority list for the whole car. I have instructed the shop to move forward on this now.
  
• All of the springs, front and back, are sagging and will need replacing for correct ride quality and height. The front shocks turned out to be 'okay', which is to say old and worn but functional. Currently has KYBs in the front. The back shocks appear to be the original factory units, and are totally past it (no surprise!).
  
• Both the front and back sub-frame connector bushings are worn, but the rears are worse than the front, perhaps one step below urgent.
  
• The balance of the front suspension, like the front shocks, is aging and worn (rubber bushings throughout, except as noted), but reasonably functional for the moment.

The shop can offer me KYB, Bilstein, and Boge shocks. I'd normally prefer the Bilsteins, but the cost difference is significant. I'm told the Bilsteins will last longer and offer a softer ride, with the KYB's offering a firmer ride (which actually doesn't sound too bad). It's a $375 price difference in the back alone, which is too large to ignore.

I'm only having the front uppers done on this trip to the shop. Those rear springs and shocks are super, super annoying, and I'll need a Plan B for that problem. There is apparently no labor overlap on the rear subframe connection vs spings/shock jobs, and the shop is quoting 8 hours for the whole back end; a hour for each spring/shock, and another 4 for the subframe bushings (which are apparently something of a bitch to replace).

Any offered advice or wisdom on suspension repairs is greatly appreciated!

 

If you don't mind replacing shocks every year skip the Bilsteins. If you want shocks that will last a while spend the money. Bilsteins will offer a softer ride does not sound right. Usually Bilsteins are a bit firmer than most other brands.

 

Dampers: If look into the recent "Suspension movement" thread that I started, you will find quite a bit of info on damper quality.

A special caveat is the lower front inboard bolts which can be real pigs to move. That has been confirmed by my local specialist workshop to be a general trend.

BTW they have experienced polys moving too easily causing squeeking and has reverted to genuine Jag metalastic. Cheap copies are to be avoided, particularly when you pay to have the work done.

Do check damper vs complete coilovers at the rear pricewise. There is hardly any difference but saves time in the workshop.

 

The front upper control arm bushings alone don't have much labor overlap to anything else. However, that is the first step to most of the rest of the front suspension. The ball joints would probably be next, and then the lower control arm bushings and springs. Also, outer tie rod ends can make a big difference.

I just bought a set of King springs and KYB shocks - hopefully I'll get to install them next week. The KYBs are priced right. If I don't like them, I'll buy something else like Koni shocks. I also bought a set of poly upper and lower control arm bushings and upper and lower ball joints - again, haven't put them in yet.

The rear strut assemblies are really easy to change. So are the front shocks - virtually no labor overlap.

 

i run KYB struts on both of my Grand Prixs and love them. nice and firm.

 

If the rear subframe mounts are totally shot and you jack the car by the jack points the rear end WILL fall out of the car. I did mine while I had the rear end out of the car and they are not that difficult - the hardest part is lining them up. I found if you do them 1 at a time makes it easier to line up all of the bolt holes. Doing it this way should take you a couple of hours to do all 4.

Shocks - well it really depends on how much you want to spend. Biltsein GAZ and Koni are top shelf. If you are happy with KYB then stay with these. Replacing rears is pretty easy you will just need a spring compressor. I made my own using the rear brake rotors for the rears shocks. You could use a couple of bits of 8-10mm steel plate with holes for the shock.

Front shocks are easy - relatively.

Front subrfame bushes - rears are easy just support the subrame and drop it enough to get at it. Fronts are not as easy in situ. But can be done without removing the subframe after you have done the rears. Undo the bolts and drop the front of the subframe undo the bolts holding the clamp and remove the bushes. You can install poly here. Reinstalling - lining up the bolts this is quite tricky as the subframe has the weight of the engine on it so its difficult to maneuver.

Hope this helps

 

Thanks for the replies, guys! Second and third opinions (or more) is what I signed up for.

I have to admit I'm thinking about trying to do the rear suspension myself. The shop my jag is in now won't install parts that aren't sourced by them. The shop manager quoted me something over $180 a piece on the Bilstein rears. It seems like I could save some money and gain more control over the parts selection doing it myself.

However, there are a number of risks I can't ignore. This is not a project mutt I brought home to keep broken in the garage; I need to keep this car on the road. I've done engine tear-downs and brake work in the past, but I've never messed with springs or struts. I've certainly never worked on a Jag.

On the plus side, there is a new facility nearby that rents out service bays, tools, and even ASE-certified tech advisers by the hour. I can rent a service bay with a lift at $177 for a full day.

Given access to to a lift, proper tools, and a little help from friends, how much do you think a DIY first-timer could accomplish on the rear suspension in a day? Or, given that this isn't a car that can sit in pieces in my garage for weeks if necessary, is this perhaps a bite more than a noob can chew?

 

How much time it takes will depend on a too many factors

If it were me I would do it bit by bit.

Rear subframe mounts first - these can be done in the garage with a jack. I would estimate 2-3 hours for a first timer. Do 1 at a time so as to keep them lined up - this is the hardest part.

Next you can do the rear shocks these can be removed with the rear in the car. You could take them to your local suspension shop and have hem fit the springs for you.

 

Agreed. Getting the differential out involves disconnecting the brake hose, driveshaft, and (agh) the exhaust, which can be a pain if rusty. If the differential is okay (not leaking) and the rear brake rotors and calipers are working properly, leave the cage in the car. Change the rubber mounts as suggested above one at a time. On another day, you can change the rear shocks out. That would also be a good time do the rubber bushings on the radius arms.

Shop around for shocks. Use Google Shopping and sort by price, searching using the shock part number. I think I saw Bilsteins for $130 or so each shipped.

 

Just IMHO but unless they're *seriously* sagging or broken, I'd leave 'em alone. The history books are plum full of woeful tales from those who have replaced springs and ended up too high or too low....

Cheers
DD

 

Thanks heaps for the reality check!

Working the rear subframe connectors one at a time seems pretty smart. Tasks that are simple but time consuming (and thus expensive) are good candidates for DIY projects.

I'm keen on the back shocks because that much back-end movement on a Jag is doubly embarrassing. (Make that a triple: !) Also, having driven a '99 Camaro SS with the Level 2 Bilstein suspension for the last 13 years, this may have exaggerated my sense of body movement in a 2-seater.

Once I get the car back, I'll begin gathering the requirements for piecemeal rear subframe mounts.

 

I forgot to mention when replacing the rear mounts - when you install the new one leave the nuts loose on the subframe - jack to SF back into the car line up and install the chassis bolts then tighten the nuts.