ural 375 diesel road test

[Trapper Ind]

just road tested our ural 375 (diesel perkins td) it went like a train, we reconditioned the brakes but the air over hydraulic brakes are very good but have a bit of a delay when braking it did 75k on the flat
any one else have similar brakes on their ural?

[paulob1]

did the brakes come on really hard after the delay, thats what i find on one of my 375's, one is reasonably progressive the other on off nothing inbetween. Cannot find out why but assume the valves air side are slow or stiff to react...

[Trapper Ind]

HI Paul,
Yes they did... put foot on pedal and take up slack (air) then press a little more (hydraulic) and brakes come on hardish...
will have to check it out some day..if we find problem i will let you know..
Nick

[paulob1]

I just tend to pump the brake and it works fine, but |i am sure there is a valve stuck or opening badly or dirt in the main brake unit...I have played with it and sprayed into the air system with wd 40 but all to no avail...

I prefer the brakes working like that than when one system failed and i was left with just the back two wheels brakes on the back up system, it did not slow the truck quickly at all, I nearly totalled a little car in front of me...luckily I could move to the outside of the lane becasue nothing was coming the other way or it would have been curtains for her car...

[Trapper Ind]

Paul,
I think i might know what the problem is with the on/off brakes... it is probably the air actuator which powers the brake master cylinder sticking, we had a similar problem on our brdm2.. take it apart and you will probably find its piston is ally and the bore is steel
Nick

[paulob1]

that may be the answer.. I have a spare one and the plan was to rebuild it and see if I could identify the problem....