Post Number: 803
|Posted on Tuesday, 01 May, 2018 - 05:11 am: |
I am determined to get back on this project: my '77 SY-series locks the brakes when they develop pressure after starting the engine. This first happened about 1 year ago. I opened bleed ports at the calipers until I found one pressured up and I could hear the brakes relax as the pressure bled off. In examining the distribution valves I found the rubber valve stem boots rotten, and one of the valves (lower I believe) stuck "in" (or on) so I could understand it applying the brakes. Without thinking things through, I dismantled the lower valve and cleaned some corrosion off the valve stem. I probably damaged the valve bore by forcing the valve out through it without cleaning it first. Nevertheless I reassembled with new rubber boots.
I bought a set of replacement hoses intending to replace these, but first I would like to get mobile again. My most recent test involved merely starting the engine without touching the brake pedal, and the brakes (at least some of them) still pressured up. Rather than a flaking hose internal serving as a check, I suspect a distribution valve, so I propose this test: remove and block the pressure supply line to first, the lower, then the upper, distribution valve's pressure inlet port, then start the engine. If I locate the offender, I will procure a tested used valve from Flying Spares in the UK. Comments or advice welcome (as would be a field visit from Bill Coburn, Master Yoda Rolls-Royce Problem Solver, at this point).
Post Number: 2055
|Posted on Tuesday, 01 May, 2018 - 05:30 am: |
To isolate the pressure to each valve clamp or remove the hydraulic pump feed hoses.
Post Number: 805
|Posted on Friday, 01 June, 2018 - 12:19 am: |
Good idea; thank you!