The brakes on my 87 failed. I replaced the relay, but the pump would not run. Disassembled and found the brushes worn. Replaced brushes. Now the pump runs constantly. Is this the pressure switch? I understand even a bad accumulator will just keep the pump recycling on and off, but won't keep it on.

I bought my 91 with this issue, pump running constantly. Replaced pump, problem fixed. The pump was weak or by passing internally.

The brakes on my 87 failed. I replaced the relay, but the pump would not run. Disassembled and found the brushes worn. Replaced brushes. Now the pump runs constantly. Is this the pressure switch? I understand even a bad accumulator will just keep the pump recycling on and off, but won't keep it on.

a leak in the system or the accumulator will keep the pump running constant.

i suggest you get on the phone with dick at allantesource.com .. he will have your ABS running quickly and properly.