Bendix brake valve question

[in2trux]

(09-22-2016 )biscuits and gravy Wrote:  

(09-22-2016 )in2trux Wrote:  Suspect voltage regulator.

I replaced the alternator on my pickup the other day because voltage was erratic.
Reman alternator right out of the box was bad so now I get to do it again.
Thanks Napa!

Dang, I'm surprised they burnt you on an alternator. For years I have only gone to NAPA for distributor caps, points and other ignition parts on older vehicles and tractors.

I guess it's bound to happen sooner or later. I always thought Eklin and some of their other electrical parts were a little bit better grade than the cheapo, 24 hours auto parts stores around here.

Thats what I thought too. Napa will replace it no problem but is that the quality I can depend on?

I have an old friend with an auto repair shop that complains about parts quality too.
Nothing like doing the same job over and over. Makes the customers think you don't know what you're doing.! He now insists on OEM parts. If someone wants to use something else they pay the labor if it last 5.miles or 5 months.

. Good news is I found an old time shop that only does starters and alternators,
big trucks too. Guess who's going to get my business.?

[PuroCumminsPower]

Found my problem. Relay valve under cab. About where driver seat is but under cab. I'll post pic.

[biscuits and gravy]

That's great news you found it.

How did you confirm that the relay valve there was the bad guy?

Did you swap in another one from another truck and the whole system return to normal? Or did just soapy water and bubbles give it away?

[PuroCumminsPower]

The brake valve would leak with parking brakes on or released. So with brakes on I disconnected lines marked delivery or "del" it has supply "sup" as well. I checked each "del" hose going to brake valve until I found the hose that was sending air back into the brake valve. I followed that air line and it connected to the relay valve shown in picture. I’m so glad i found it. Those parts aren’t cheap. Brake valve was like $450 and relay valve like $350.