Spongey Brakes 1985 XJ6
 

Hi Everyone, Still a newbie, this is the second XJ6 that I have owned. The car has 68,000 original miles. My XJ6 seems to have spongy brake's it seems you have to pump them to build up more pressure. I am comparing this to my previous car same year, any idea's for me to start with. Thank's so much Sharon

Start with a thorough brake inspection...any obvious defects? .... and brake fluid flush/bleed.

Cheers
DD

Spongey Brakes 1985 XJ6
 

'Spongy' brakes can be caused by a variety of factors, including trapped air in one of the lines, bulging of the flex hoses or a stuck caliper piston. If the fluid appears dark and you don't have the service history of the vehicle, start with replacing all three flex hoses and inspect the brake discs for even wear. If uneven wear is evident, especially in the rear, a seized piston or stuck pads may be the cause of the poor pedal feel.

The rear brakes on the XJ6 are often overlooked due to the cost of servicing the calipers and discs. The design is directly from a racing car with inboard discs and calipers to reduce unsprung weight and add to the car's excellent handling characteristics, but to service the rear brakes for anything other than bleeding or pad replacement requires removal of the entire rear suspension assembly complete with differential. If new discs are required, they must be centered within the caliper by placing shims in front of or behind the disc prior to reattaching the universal joints.

NBCat

Just rebuilt the front calipers on teh SIII XJ6 (6 of the 8 pistons were stuck)

been going back & forth bleeding the Passenger's & Driver's side calipers, but the brakes still feel a little squishy.

I'm not getting air bubles from the calipers anymore, so I'm starting to wonder if there is a relief valve somewhere else in the system.

also, I'm still using the OEM brake lines, which dont seem to be buldging, but I plan on replacing them with a set of Teflon/ braided stainless steel/ JIC hoses.

I just dont want to start digging through the engine bay on a hunch that there is a relief valve, that may actually not exist, meanwile accidently causing damage to the frail, but operational wiring system. (soon to be replaced, stay tuned.)

I had a similar problem that was due to a stuck caliper on the rear brakes. The fluid would heat up and the brakes would feel spongy. When the fluid cooled off the brakes would be fine. Had to do a full brake job on the rears to cure the problem. I will say that although the rear brakes are a real tough job, it is a DIY project with the right tools and a helper. Took me about 10-12 hrs to do it and that was my first time.

On to the rear brakes then!