thwaies 1 ton dumper/skip loader

[Rob boxers]

hi, I have a thwaites 1 ton hydrostsatic dumper, I drove it in to the garage for a check over and now it wont move.
it has 1 forward and 1 reverse gear, when you select either it wont release the brake.
any help would be much appreciated.
rob.

[essexpete]

I don't know much about these but at the risk of stating the obvious it sounds like and electrical glitch. How does the parking brake work?

[Rob boxers]

I don't know! and cant find a manual to read,
when not in forward or reverse the brake is activated some how stopping the fluid from circulating, ive tried swopping relays but no different.

[essexpete]

Could the shuttle switch be faulty? Or perhaps earth or feed to that area?

[widget]

There should be a mag switch at the base of the forward reverse control lever that may not be getting a good contact with the F/R control levers switch plate, worked on these many years ago and I am sure that was a common problem. I dont think the switches used to fail, dirt ingressed between the switch and the contact plate at the base of the lever or the metal used to wear away..... struggling to remember but maybe worth a look tho

[Rob boxers]

thanks guys, will check tomorrow and let you know.

[Rob boxers]

turned out to be the `timer relay`behind the ign switch.(the only one I didn't change!!).
thanks for your ideas though.