As part of my quest for a tighter air system, I occasionally run a search on eBay, looking for applicable Bendix products. The other day I scored a rebuild kit for my PP-1 valve for $15, including free shipping and no tax. This is a New Old Stock kit, still factory sealed, and in perfect condition. In case you are wondering, the PP-1 valve is the "Parking Brake" control, at least on my coach. Not sure if this was used for all model years...
There is a entry at Beamalarm on this subject, and a link to a repair kit. But after you add shipping charges, my eBay price is a better deal.
Yellow Park Brake air leak Repair (http://beamalarm.com/Documents/yellow_park_brake_air_leak_repair.html)
My valve is original, I'm sure, and still pretty tight. I CAN make it leak by wiggling the knob sideways, so the internal seals are getting tired. By having a rebuild kit on hand, I know I can renew the valve whenever the mood strikes. Always nice to have a backup plan in place, because these pesky devices like to wait for the most inopportune moment to fail. When I do get around to doing the simple rebuild, I will pull this post back up and add a little photo tutorial.
Well, I got bored today, so I decided to go ahead and pull and rebuild the parking brake valve. Like I thought, it was a very easy job - took about 30 minutes start to finish.
Remove the knob, remove the chrome retaining nut, push the valve back through the hole in the dash, and it drops down below the dash where you can remove the air hoses and wires. Take it to your bench, pull it apart, clean it up, install new parts. Assemble in reverse order.
I think my valve was leaking past the small O-ring on the plunger shaft. I am confident that I have now eliminated one more leak. ^.^d
Photos below are pretty self explanatory - just follow the instruction sheet that I posted above.
Again, good job and excellent documentation.
Thanks.
Great job Chuck. Thanks for the detailed instructions with pictures.
I did a rebuild about three years ago when mine was leaking down overnight and used a rebuild kit to replace the o-rings etc. No leaks from there any more but did find a leak last week on one of the two 60 psi check switches on the lines to the treadle valve for the service brakes underneath. It was leaking down overnight and I could hear hissing. A quick check with soap bubbles and found it easily. I replaced both of them with two from O'reileys for about $15 apiece and that slowed the leak to about 3psi per hour until it stopped at 60 psi.
I could find no leaks with the soap bubble test on the system in the front so I started looking in the back. I checked all fittings to the airbags and both rear tanks and at the ride height adjustment valve covers. Both of the rear valves had been replaced by FOT in Dec 2012 and work properly. When I sprayed soapy solution at the top of the passenger side valve where the fittings are I saw bubbles! As it turns out the brass fitting at the top of the valve was leaking so I used a crescent wrench and tightened about a turn till the bubbles stopped. The gauges on the dash read 120 psi and I checked after 5 hours. Neither tank had moved off of 120 and hopefully I've found the last major leak for a while.
Jerry
P.S. I found one of these hats at Autozone for $10. It has two strong LED lights in the brim that work great at focusing light where your eyes want to go. It's great for working underneath the rig in the daytime or fumbling for your keys at night. You can free up both hands and protect the skullcap at the same time!
Great report with good clear photos, Jerry! I checked around that area when I did the rebuild on my throttle valve. Everything looked tight, which was a relief. I would not look forward to doing a R&R on the brake treadle valve. What a tangle of air lines and fittings! But replacing the 60 psi switches doesn't look too bad. ^.^d
I am still looking for a pesky air leak that drains my wet tank from 120 to zero overnight. I have replaced both the check valves on the wet tank, with no improvement. I will take your clue and check those fittings on top of the ride height valves. If that doesn't help, my next step will be to install a 1/4 turn ball valve on each line coming out of the wet tank. Then, from a "aired-up" condition, I can close all the valves, sealing off the tank. Assuming the tank itself does not have a pin-hole leak (not impossible), then I will open the valves one at a time until I find the offending line. Then find the leak in that line.
Isn't chasing air leaks FUN! Who needs a hobby, when you have a air-suspended coach?
P.S. I got me one of them "headlight" caps at Walmart. Also works great for walking the dog in unfamiliar RV parks at night!
Do our Foretravels have a check valve on the line from the compressor to the tank? That is where I usually find a big air leak on one of my trucks. The air goes back to the compressor and leaks by the rings. I am still learning about the Fortravel air system at this time.
Air flow is from compressor to air dryer, then from dryer to wet tank. There is a check valve at the drier, and another one at the inlet to the wet tank.
If everything works right, air cannot flow "backwards" out of the wet tank.
Just for something to do I would take the line and check valve off at the Air Dryer and see if it is ok as I found mine to have been replaced in the wrong direction (reversed) when years ago and before the pit I had FT do some service work on one of our trips thru there. Could not believe it and the spring was damaged because of that too. I replaced the check valve on tanks at same time.
JohnH
Thanks John, that is certainly a good tip. However, I verified that the AD-9 delivery port check valve was installed properly, when I replaced my dryer 2 years ago. In fact, I think I checked it specifically
because of reading one of
your old posts on that exact subject! Since I know it was OK at that time, and I just recently replaced the check valve on the wet tank inlet, I'm pretty sure my line from dryer to wet tank is "tight".
Photos: The check valve is retained by the big brass "nut".
[quote author=Chuck & Jeannie link=msg=233880 date=1463922747
Chuck,
I had some more fun today when I found I was still leaking down to 65 psi after finding the leaking ride height valve fitting yesterday. Another easy find and fix. The control valve for the aux air line was leaking. It was too easy to turn on. I could hear hissing and in the off position it wasn't hissing but still leaking using the soap bubble test. A simple tightening with a crescent wrench and the valve is much tighter to turn and the bubbles are gone . After that I aired the coach up to 130 psi and we will see what happens overnight!
Jerry
Chuck
Two things to try
1) Put some glycerin in with your soap solution, depending on how big your spray bottle is, maybe 1 tablespoon. It helps the soapy water stick to the hosing.
2) Spray the living daylights out of your supply line to your D2 govenor. I have seen many of these hoses FULL of tiny little pin holes. You can't hear them but if they are there they will drain tanks no problem. Hose it down with soapy water and just wait. If you see any kind of bubble or froth, change the hose.
Good luck.
Another good lead, and one I haven't checked yet. I
should have covered this one already, since that line comes directly off the wet tank, and my valve is also very "easy" to turn. I keep thinking I should be able to HEAR a fairly substantial leak, but I guess that is a false assumption. Especially since I can't hear half the things my wife says to me...or perhaps that is a different problem. ;)
Thanks! I will definitely look at that valve!
Thanks for that excellent tip! Keep them coming, Guys! This is the true value of this Forum! You shouldn't have to reinvent the wheel every time you have a problem with your coach. Odds are, another member has tackled the exact same puzzle, and found a solution. At the very least, knowing logical places to start looking can get you on the right track, and save lots of time.
Soaping the D2 supply line is now on my "short list" next time I have the coach up on safety stands.