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R12 & R14 Relays
In this schematic it shows the E-brake relay is the R14 relay but drawing looks different and 1 of the R12 relays is for the drives and going to the tags there is also 2 more relays at the tags that they don’t say R12 on them they say Valve interlock LH & RH Left side Right side & have 2 different Prevost part numbers on them, but isn’t there one R14 relay for e-brake and three R12 relays for drives and Tags, different between R14 & R12 relays is 1 more port on the R14 relay??
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10 Replies
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Art
there was a SB-14? which has to to with TAG AXLE LOGIC…..the dreded lifting of the tags if AUX air drops below 35lbs.
Maybe your coach has had this costly fix done already.
Jonathan
96/97 XL40 Royale # 201
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Yes mine was built when they did not use the reverse logic so it will not drop and it has the inversion valve. That drawing is after the reverse logic
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The tag logic ended about 1994.
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So im I right about the R14 and the R12 valves???
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The function of the R12 & R14 relays are the same. The difference is the extra port on the R14. When replacing a R12 with the more current R14 relay, simply plug the unused ports.
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Your brake relay valves have nothing to do with your tag logic & SB96-14B, well not directly. I thinks the tag brakes are disabled when the tag is raised, but brake relay valves work brakes, not tag bags.
R12 & R14 brake relay valves and their rebuild kits are readily available and one need not be used in place of the other.
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Here a thread about rebuilding them and a bendix parts catalog. Look between pages 40-50 for the parts
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When I was messing w/that stuff on my bus a few yrs ago, the two relay valves above the tag, 141865 & 141866, that Prevost calls “interlock” valves look identical to the drive axle R12 relay valve, 141867.
The R14 looks different and has a very different part# 141644.
Notice how the 3 that look the same have nearly identical part #s. My bet is those 3 are all R12 relay valves regardless of what prevost labels them. I suggest you call Prevost or Jeff.
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I looked over SB 96-14B. Prevost did NOT change any of the relay/interlock valves to accomplish the logic change. They did change/add fittings on some of them.
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The part#s I was referring to came from diagram D-140212 Rev C , here’s the link:
He is SB 96-14B
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