Displaying items by tag: Suspension

While doing all the right things on the MK2 front end I stripped it out completely and had the major components sandblasted. I was contemplating what sort of paint finish I would apply when an acquaintance of mine suggested a paint I had not heard of before. It is Ronstin’s Rapid Dry Industrial Black Enamel. He said he had been using it for years for chassis and sub frame painting and it stood up very well to the abuse and knocks that come with the under vehicle territory.

I purchased some at our local automotive paint outlet in Brendale and was pleasantly surprised at the price that was a tad over $13 per litre. It did require some thinning to spray but covered very well with a really deep black gloss. The quick drying part lived up to its name, as I was able to handle parts within half an hour of painting. As an experiment I really loaded up some areas with paint, which would have produced runs in a standard enamel, but it did not display any propensity to run.

The rear axle of the MK1 and 2 is located on the extreme end of the rear spring leaf and is controlled by a torque arm on either side of the car running from a body mounting to a bracket on the axle. This then locates the axle in relation to the body and stops the spring winding up under acceleration torque somewhat like a trailing arm system. The torque arms are fitted with metal/rubber bushes and with age these deteriorate with a subsequent loss of “stiffness” in axle location and general handling suffers. Don't confuse the torque arm with the panhard rod, which runs laterally [across] the car from the right hand side to near the differential centre. It centres the rear axle and suspension.

On the red MK 1 I knew that these bushes were getting pretty bad. Every time I jacked it up I could see daylight through the rubber area of the bushes. I obtained a new set from Jag World [PH 3272 7287] and with some help from a friend who is a club member we removed the torque arms, pressed out the old bushes and inserted the new bushes. Note-I have seen an illustration of this operation in a UK magazine using a bench vice. They must be different over there because we used almost all of the force of an 8 tonne hydraulic press to get the old bushes out.

We also found that the right hand body mounting for the torque arm was cracked and required some serious oxy welding to repair before refitting the torque arm. It also helped that this fellow club member happens to have an electric/hydraulic two-post car hoist in his private shed. This made the job much easier.

There was no doubt that as I drove the red MK1 home that evening along a winding high-speed road that the handling had vastly improved

When it came to getting the white MK1 through a roadworthy one item that became obvious was that the rear shock absorber mount rubbers were completely perished and new rubbers would need to be fitted before it would pass. With that in mind I had the car on ramps at home and fitted the new rubbers by the time honoured system of lying on the shed floor and applying much grunting, effort and some amount of cursing.

Whist lying on the floor I recalled what Tony Herald had said about how he cleaned under his concourse car and thought why not start here? So I degreased and cleaned up the diff and the general areas under the spare wheel well and petrol tank area and subsequently applied some black paint etc. It sure looked better.

To my surprise when the car was on the hoist being checked for roadworthiness I noted that a patch of my new paint on the differential had been scraped back to bare metal. I then realised that the odd suspension noise that I had heard was not a noisy/squeaky shock absorber but was actually the differential occasionally rubbing on the body area immediately adjacent to the petrol tank. I did not point this out to the chap doing the roadworthy and he was more interested in tie rod ends etc. The torque arm bushes looked OK but more on that later

After getting the car registered I organised use of the previously mentioned club members hoist. Mark Miosge from North Qld. Jaguar Spares in Mackay [ph 07 4954 6003] had offered me a good deal on a pair of torque arms he had overhauled with new bushes for a customer who had never collected them. I had acquired them “just in case” I needed them. When we removed the old torque arms the bushes literally fell apart so what looked OK was in fact totally “shot”. The new torque arms were fitted with a subsequent improvement in handling and the elimination of the occasional squeak.

I have since noted that the red MK1 has a patch welded on the rear of the diff housing just where it would rub on the body. I presume this is an old battle scar from a previous occasion when the torque arm bushes flogged out

A number of club members have get involved in the ride height debate for a MK 1-2 Jaguar. It appears that 18 1/2 to 19 inches from the ground to the centre of the boot lock is about right.

However members of other registers have also done investigation into their cars and have found some to be well and truly in need of serious adjustments and repairs to the rear end. Malcolm Imrie who wrote an article for the Bits and Pieces section of February magazine on XJ6 rear springs provides a good example of “getting it right”.

The MK 1&2 Jaguar workshop manuals are a little skimpy about ride height for the rear end of these cars. Everybody knows that the correct height for a front end is about 3 finger widths between the top of the tyre and the bottom of the mudguard arch. In the workshop manual there is a specification for the amount of curve in the rear springs but that is about all.

It was not until I had the two MK 1s in the shed that I noticed there was a completely difference in the way the cars appeared to “sit”. The red car was definitely lower in the rear end. With a tape measure I checked the height from floor level to the centre of the boot look . To my surprise I found a difference of 2 ½ inches. The red one measured 16 inches and the white one 18 ½ inches. The difference really becomes apparent when you realise the red one is on standard 185x15 tyres and the white one is on 205x65x15 tyres that have about ½ inch less in tyre profile height.

I would appreciate any feedback from MK1 and 2 club members on the specific height measurement on their cars along with the types of tyres fitted. We have checked another club members MK2 and it appears 18 ½ to 19 inches to the bootlock centre is about right on 185x15 tyres.

I always thought the red car looked to be “dragging its bum”. Once I have established the correct height it is off to the spring works for resetting

With two MK1 cars with sagging rear springs it was time to adopt production line methods. Mark Miosge from North Qld. Jag spares in Mackay [ph 4954 1420] mentioned that he had a good pair of springs and offered them at a reasonable price. In fact the freight was nearly as much as the springs. Inspecting them on arrival showed that they were good and did not require any re-setting. I visited Barry the friendly spring man at Pine Rivers Spring works [ph 3285 7383] and got him to fit the new spring eye bushes and rubber mounting blocks that I supplied.

A couple of hours under the car including welding up part of the left hand spring mounting box and the red MK 1 3.4 was back into action. It really does sit correctly and this is emphasised when the two red MK1s are sitting adjacent to each other. There is a really apparent rear end sag in the 3.8 car. The springs that came out of the 3.4 will be re-set and have new hardware fitted before going into the red Mk 1 3.8. I will then have a spare set of rear springs so if anyone is desperately in need of them contact me.

IS Bigger Better: LET'S TALK ABOUT THE BALLS IN YOUR JAGUAR'S FRONT SUSPENSION.

The traditional Jaguar lower ball joint is assembled into the Stub axle carrier. The wearing parts (i.e. the ball, the socket below the ball and the spigot above the ball) are separately replaceable. The clearance is adjustable and is set using shims. Wear tends to be localized, so it is possible (although not best practice) to give worn assemblies a new lease of life by rotating the ball and spigot through 180. A grease nipple is provided. The procedure for assembly and adjustment of these old style ball joints is rather tedious, and in today's high labour cost environment it is not economically viable except for the do-it-yourself enthusiast. Today Jaguar uses a sealed-for-life ball joint which can be retrofitted to many older Jags including E-Types. The assembly is pre-lubricated with no grease nipple. Given the high load carried by these joints, I decided to disembowel a modern sealed unit and to compare its ball with one of the original design.

The most obvious difference is the diameter of the ball. The modern item has a diameter of 25 mm whereas the diameter of the original part is 38.1 mm. All other things being equal, the larger ball will last longer. Notwithstanding the smaller diameter of the modern ball, Jaguar have contrived to have its centre of rotation at the same point as the original, so the front end geometry of older cars is not affected if the modern ball joint is used.

Unfortunately I believe the original specification, chrome plated balls are no longer available. Therefore, those who use the larger balls are obliged to buy an inferior aftermarket copy. Gone is the hard chrome plating and the smooth surface finish. Instead you get a ball turned on a CNC lathe complete with turning marks and various "dings' resulting from careless handling in bulk. These surface imperfections benefit from some detailed dressing and polishing in a lathe. The aftermarket kits also contain a rubber boot which will perish within 12 months. Discard the rubber boot prior to use and replace it with a nylon boot.

Despite all these shortcomings, I continue to favour the larger original style ball.