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BRAKE PRESSURE LOSS
Just shooting in the dark but someone may have had this issue.
When I shut off the engine with brake pressure normal and parking brake set, both primary and secondary brake pressure tanks proceed evenly to 0 in about 20 minutes.
Any guesses?
1999 XLV X-6872, liberty #440 -
5 Replies
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I’d check the PP-1 valve first. I had a similar issue. Just by releasing and reapplying with authority, the bleed down stopped on primary for me. I haven’t replaced the valve, yet. It might of been more of user error for me.
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Maybe Bendix R-14 brake relay valve, p.47:
https://www.bendix.com/media/documents/BW1114QuickReferenceCatalog.pdf
and my rebuild w/pics
/threaddetails.asp?Category=Pneumatic%3E&ThreadID=6143
Bad/fast enough you should be able to here it?
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Thanks for the replies.
Went to check out bus this am. Yes, you’d think I’d hear a leak of this magnitude. Crawled around under bus for about 20 minutes with my spray bottle and couldn’t find a leak. Went up front to see if there was any pressure left in brakes and both tanks were still at about 70 psi!!
I’ll figure it out eventually.
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That’s still a pretty good leak if it’s going from 120 to 70 in 20 minutes.
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What is the aux air pressure doing? If t is dropping, the check valves on tank 1 and 2 as well as the protection valve at the aux tank could be bad. If it is holding ant the tanks 1 and 2 are dropping, then check the parking brake valve, the treadle valve.
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