Tracing an annoying rattle
On a recent trip in the Jaguar over some of our local roads that in no way could be described as smooth, I could hear a new light rattle that appeared to come from under the car. It was a higher frequency sound that seemed to indicate it was something small which was loose, so that ruled out the exhaust or any other major item. I thought it may have been something connected with the handbrake mechanism, which has always produced a light rattle, but at a much lower volume than could now be heard.
The car was placed on the hoist and raised for an examination of the underside, and the mechanical handbrake linkage came in for immediate scrutiny. The E-type has rear disc brakes, with separate small brake pads for the handbrake that are operated via a cable from the handbrake lever to a compensator mounted on the rear subframe. Applying the handbrake pulls together two levers in a scissor action, which transfers the motion to clamp the handbrake pads to the discs.
The compensator on my car is original, so consequentially many of the pivot points had a degree of wear on both the holes and clevis pins. I had earlier made efforts to overcome the wear in the mechanism where possible by improving the fit of all the clevis pins. Several of the lever holes were oval, so they were drilled to a slightly larger diameter and special clevis pins then machined from stainless steel bar with an increased diameter so they were a good sliding fit in the resized and now round holes.
Where feasible during the reassembly, springs and washers were fitted in an effort to reduce all slackness in the assembly and remove the rattle. However, this has only been partially successful, as there are still a few pivots that are riveted and require major surgery to remove all the play. That’s why a slight rattle could still be heard, but usually only when driving adjacent to a solid barrier that reflected the sound back to the car.
A careful examination of the handbrake mechanism now did not indicate any additional play in the components that could explain the increased noise volume, so I looked elsewhere. I have fitted a heat shield between the two silencers and the transmission tunnel to reduce the amount of heat being transferred to the cabin. The shield was made from a sheet of aluminium that has reflective sheet insulation glued to the underside, the same material with which I had lined the underside of the transmission tunnel. The shield is attached to the car with four 3/16in pop rivets, and I noticed that the two pop rivets at the rear of the heat shield were no longer attached to the car, allowing the rear edge of the shield to rest on the silencers. This was the likely cause of the new rattle.
There is only a small gap between the silencers and the car floor, so the exhaust was going to require removing
to gain space to drill out the old rivets and fit new. I was reluctant to unbolt the exhaust front pipes from the exhaust manifold, which is a fiddly job with limited access and may result in exhaust sealing issues. So as there are lengths of flexible pipe at the bottom of the front pipes, I reasoned that if I left the manifold joints in place, I could unbolt the brackets from the rest of the system and the flexible pipes would allow sufficient movement for the back section to be lowered, giving access to the heat shield fixings.
With the rear of the exhaust supported on a trolley, there was indeed sufficient room to allow drilling out of the old pop rivets using an angle drill and short drill bit. Also, after removing the rear container for catching the rivet stems, I was able to gain access for my air riveter for refixing the shield, which was considerably easier than trying to fit the 3/16in rivets by conventional means. After securely fixing the heat shield, the exhaust system was refitted and all of the underside checked for other possible sources of the noise. Nothing could be located, so I was confident I had been able to silence this new rattle.
Whilst the car was on the hoist, I took the opportunity to perform its annual service. I keep a maintenance log on an Excel spreadsheet for both the Jaguar and Stag, and I was aware that they were both getting close to service time. The Jaguar does not cover a large annual mileage, less than the handbook’s 3000mile recommended point for requiring an oil change, so I always complete an annual oil change together with a replacement filter, in spite of the recommended point for a filter change being 6000 miles. I view the regular oil and filter replacement as being a lowcost insurance against excess engine wear, and as I have converted the Jaguar filter to a modern spin on type, it is a lot less messy to change than the original canister style.
The car has a large sump that requires 8.5 litres for a refill including filter, and this requires a larger than normal oil drain pan. I now have a 15-litre pan after struggling in the past with having to use two 5 or 6-litre items. An oil change is always a bit messy, but at least the larger pan reduces the clean-up required after. I always use a premium mineral oil in both the Jaguar and Stag. The Stag has a 4.5-litre capacity, so when I see it on sale, I purchase three 5-litre containers and that is sufficient to complete an oil change on both cars.
At the annual service, the levels in both the differential and gearbox get checked, and all the grease nipples in the suspension receive a clean and a few pumps from a grease gun to ensure that they are correctly lubricated. The air filter element also gets checked and replaced if required, as does the fuel filter where the original gauze has been replaced by a filter element. All wheel bearings, suspension and steering joints also get checked for excess wear, and hopefully we’re good to go for another year.
“I could hear a new light rattle coming from under the car”