Tag brakes on 87 102A3

[hargreaves]

I'm in the middle of relining the tag brakes on my dear old girl and low and behold I found an air leak. It is coming from what looks like the pressure reducing valve that is in the air line  going to the tag axle. 

Does anyone know the pressure that it is supposed to be set at? I am hoping to rebuild it if there is enough body left.

Thanks in advance      Gerry

[JackConrad]

    Is this air line going to the tag axle brake or tag axle airbag?  On our MC-8, the manual says the tag axle brake regulator should be adjusted to 25-30 PSI.  We set ours at 27 PSI.  Jack

[hargreaves]

Hi Jack,  Just finished doing a road test, rebuilt the regulator, it was siezed solid. Noticed after the test that the rear brakes were quite hot - I was using them quite a bit, but the tag brakes were just warm. I see the slacks coming on .

Thanks for the info, Do you know why they regulate the air pressure to the tags.? I notice the chambers are quite small already. Do they do this to keep them from locking up?

      Gerry           PS It sure is nice to have brakes again.

[JackConrad]

Thanks for the info, Do you know why they regulate the air pressure to the tags.? I notice the chambers are quite small already. Do they do this to keep them from locking up?
Gerry

     Yes, our MC-8 was one of the first and did not have the regulators. We had a problem with the tags locking up when we made a hard brake application (when the traffic light changes at the last moment or that idiot pulls out right in front of you).  Since adding the regulators, we have had no problems.
     We installed a brake application pressure gauge when we made the new dash.  Normal braking is usually no more than 15 PSI. I think the reason for the difference in temps on the rear brakes is due to a couple factors. Drive axle has larger diaphrams, larger drums and more weight on that axle.  Jack

[hargreaves]

Thanks Jack, I will put an air gauge on them and set the pressures.

Gerry