Air pressure SP36

[Bob Lawrence]

The rear spring brakes lock up at 60psi per DOT. You probably have the
rubber valve torn in the can.
I just replaced both of mine (no problems, just precaution). The now
have double cans to put on so you have a backup.
When driving my 18 wheeler a couple of years ago going down a mountain
ineastern Washington, one of the cans on the tractor sprung a leak and
every time I put on the brakes, you could hear the hissing. Managed to
make it down by really relying on the jake brake. Had it changed out on
the side of the road.
It is not a big job, but I wouldn't try it yourself as the brake can
spring needs to be caged to release the brake.
Drive slowly to a truck place or have them come out to you.
Bob Lawrence
84 PT36
Tacoma, Wa.

>
> I was waiting in line on a slight grade at a Flying J with my
> foot on the brake (probably 1 minute) and I noticed quite a drop
> in air pressure and then my steps came out. I set the parking
> brake until pressure came back up and the steps retracted.
> Is this normal, and if not, what corrective action need I take?
>
> Chuck Harrison
> Akron, Ohio
> 90SP36
>