I've received so much help over the years from the forum I thought I'd reach out for some advice before purchasing a New Tandem Master Cylinder for my XK120. I've finally have my machine running and am just finishing up on the brake system. I changed out all 6 of the wheel cylinders, new hoses, had my brake drums turned and brake shoes refitted. I've worked for some time bleeding the brakes, finally had a close friend bring over his pressure (Wagner) machine. We had tried previously by using 3 people at right rear and left front bleeder valves at the same time, we've pumped forever. The pressure method has the fluid running clear, systems seems clean and no bubbles. I've use at least a quart and half of fluid. I've ordered out another quart of DOT 4, but thought I'd check with other 120 owners to see if there's any tricks that we're missing. Still have a spongey brake pedal. Before I order out a new Master Cylinder I thought the Forum was my best bet. Thank you sincerely george young

 

first thought is I see all the new parts but do not see that the brake shoes were adjusted to the drums before you began bleeding. if not you will never get a pedal of any satisfaction. While talking adjusting have you adjusted the free play in your master linkage? Good luck!

 

Adjusted to the (9,s) front shoes are auto adjust. Replaced the rear hose and that seems to be helping out. The shop manual said the hose was on the Right Rear but my 120 has it on the Left side. I've got pedal so I'm going to run it for a while and try wearing in the new shoes. Thanks so much for your input. george

 

Hi George,
Just wondering if you ever sorted the brake pedal problem? I'm having similar problems on my 120.. I didn't bleed front and back at the same time, just did each wheel individually.
doesthis make much of a difference?
Regards,
Scott

 

A friend came over and took my Jag his shop and did it. Also a little body work
He has a restoration facility. Finally have the vehicle back on the road. Really appreciated all the comments and help I received. George

 

Actually here is the situation that I encountered with my XK120 Tandem Brake System. We were expelling the air from the system. the brake shoe auto adjusters were adjusting then relaxing and that they had to be fixed up so that they would adjust and stay adjusted. Otherwise the hydraulic lines could be air free but still not have enough pedal to move the shoes the right distance. I definitely would have two people tackling the task. The Auto Brake adjustment feature on the XKX120 was a big part of the problem. We weren't getting the brake shoes close enough to the drum surface.

 

Hi that's interesting I think that might be the case with mine. I adjusted the auto adjust mechanism and it improved the pedal slightly..I'll keep you posted!
Regards Scott

 

Driving my XK120. The gas gauge and speedometer are acting up. I could use some advise on first tackling the fuel gauge. When I energize the control panel by turning on the ignition the needle on the gauge jumps slightly, When it's turned off the gauge needle swings down slightly. I've put in 6 gallons of fuel and it should indicate 1/3 or more full. If anyone out there has experienced a similar problem please let me know. thanks

 

Hi George,
I haven't had that problem..my guages are all over the place but want to get it reliable first!
It would suggest a broken sender,
more than likely the float unit in the tank could be siezed if it's been sitting around for long. Good luck
Scott

 

Thank you It was in fact in the sender unit. There was some accumulated deposits on the sender arm. Cleaned it up, worked it back and forth and reassembled the unit. Working very well now.. Thanks so much for your comments.

 

Just to let you know.
I adjusted the self adjusters on the front brakes so they were quite tight, still free to go back and bled front and rear at the same time.. I've a great pedal now! Thanks for all your help 😊