Brake master cylinder replacement
Whilst I was out driving my 1989 Jaguar 3.6 XJ40 just recently, the brake pedal began to feel soft and the travel seemed far too long. After a quick check, I couldn’t find any brake fluid leaking out of the system and the car was still pulling up in a straight line, so I concluded the master cylinder was at fault. As this happened very close to my local MoT garage, I popped in and asked if I could put the car on their brake test rollers. Luckily they were free and a quick test showed that although the front brakes were working fine, the rears were well below par. The general consensus was that the master cylinder was at fault.
Once home I didn’t want to remove the old cylinder from the car before having a replacement ready to fit as this would make car totally immobile. Therefore, I purchased a second hand master cylinder, servo unit and a brake fluid reservoir as a complete assembly from Rob Jenner (rob@exclusively-jaguar. co.uk) and had it delivered to Nigel Wigg at Past Parts of Bury Saint Edmunds, Suffolk (www.pastparts.co.uk) to be refurbished. A couple of weeks later the same unit was returned to me clean, shiny and totally refurbished, ready to fit to the car.
Before removing the old master cylinder, it was necessary to remove the bolts holding the power steering reservoir to the inner wing. This allows easier access to the hydraulic pipe-fittings on the side of the master cylinder and the tandem mounted servo. Once that was done, lots of cloths were placed beneath the reservoir in order to catch any lost fluid. After removing the brake fluid reservoir cap with its electrical connectors, the pipes to the master cylinder were undone, followed by the lines to the servo, after which the four bolts securing the servo to the pedal box were then removed.
Before the servo could be lifted away from the car the brake pushrod from the pedal box needed to be detached. Getting the two rubber bungs away from each side of the pedal box was easy enough
Relocating the clevis pin to the replacement servo was easy enough of course but then getting that retched retaining clip back in place was unbelievably fiddly
but getting the retaining clip of the end of the clevis pin proved a devil of a job. Then when it came off the perishing thing dropped into the footwell.
Relocating the clevis pin to the replacement servo was easy enough of course but then getting that retched retaining clip back in place was unbelievably fiddly. Eventually it went on and then the two servo pipes were reattached loosely followed by the four bolts securing the servo to the pedal box. The ‘new’ master cylinder was then attached, again just loosely until the threads on the brakes pipes were started. Once the pipes were in place, all the bolts and unions were tightened and carefully checked.
After refilling the reservoir with fresh brake fluid, the brakes were bled until I was satisfied there was no air left in the system and the pedal felt good. The final job was to refit the power steering reservoir to the inner wing and after this was done I went inside to clean up before taking the car for a road test.
However, when I came back out to the car I realised that the nearside front mud flap was hanging off. It must have been dislodged while I was attacking the bleed valve on the caliper at that corner. So it was back into garage to break out the drill, a screwdriver and a handfull of new self-tapping screws so the errant flap could be reattached to the car. However, after a closer inspection it looks like I’m eventually going to have to deal with some minor corrosion behind that mud flap. For now it is quite secure though and out on the road at last a brief drive showed all was well with the brakes. With the newly reconditioned master cylinder plus the EBC discs and Red Stuff pads fitted earlier, the pedal feel is now perfect and stopping power back to excellent. Another job well done – despite the unfortunate delay.