My Lull brake booster often sticks so that the only brake fluid that returns from the 8 wheel cylinders is the volume of the master cylinder- not the booster cylinder. The result is that not all the wheel cylinders release therefore a brake hangs up. I have removed the extension from the booster and worked the rod by hand (sometimes I find it stuck out and a gentle bump makes it jump back in) and the brakes work well for a few dozen times then it goes back to sticking. Any ideas onwhat could be causing this? Bill Klein
Think I would be looking at the piston in the booster master cylinder. If the bore is not to bad maybe able to put a kit in it. Possibly just buy the cup seals from Napa. Parts maybe available from a local truck parts supplier or a reman from Bepco. I have had great service from JLG but parts are high. Look on line for a service manual. Some models have free PDF parts and service manuals.
Thank you for the reply Tenwheeler. The booster cylinder was my 1st thought also but when I removed it from the front of the chamber the rod was still stuck out. I had to give the rod a bump before it retracted with a jump. Is there a shuttle spool or the like in the base that the cylinder extension screws in to? Bill Klein
What model Lull do you have ? I can send you the manuals in pdf form .
It is a TT644 Telehandler. Thank you.
Do you have a picture of the machine with serial number you can email me at [email protected] .