tag axel dump problems

[Jim Barone]

This is Jim Barone, fulltiming in a 1991 PT, currently in western Kentucky. My tag axel will not dump. Tomorrow I am taking the coach to a local truck repair shop. The mechanic is very familiar with air suspension systems for over-the-road trucks but has never seen a Bird. The problem is either a bad valve or an electrical problem. How can I guide him to the problem? If the problem is simply a bad valve I'm sure he can R&R it. If the problem is electrical, is there a relay involved and if so, where is it? Again, Thanks for all your help. Jim Barone

[Rob Robinson]

Jim I'm glad you have time and not stuck on the road side. You'll get an answer today or this evening before you have to head to the mechanic. Many of the 91 owners and BB experts are busy during the day but before long they'll be on your problem like 'white on rice'. Hang in there.

[jyclegg]

Jim

There are 3 little solenoids in the electrical compartment on the front of the coach. These provide the air control to the dump system. There has been a thread on this forum about where to get new ones. Good Luck

[fxdwg]

I don't know how close your's is to mine, but my dump valve is located right over and slight behind my tag axle. When you slide under and are looking at the tag axle, just turn around, the valve will be right in your face. Mine sticks on occassion, and rocking the switch a couple of times usually clears it, but I haven't had her out in the colder weather we're seeing so I don't know if it will still "fix" it.

[mbrund]

Originally Posted by jyclegg

Jim

There are 3 little solenoids in the electrical compartment on the front of the coach. These provide the air control to the dump system. There has been a thread on this forum about where to get new ones. Good Luck

As Jon has stated, pull the nose cover off and look toward the drivers side of the coach for 3 clipper valves. They will have a yellow cover on them. Start there and see if the one for the Tag is having issues.

[jwasnewski]

James, I am not suggesting that the problem is electrical or mechanical. I am suggesting that you give the mechanic the full history of your aux air system, including that it filled with water 8-9 months ago when the air purge protective check valve failed. It may save you a few dollars in troubleshooting.

I cannot tell from my prints without studying the air prints what the relays do. Fuse SK32 15a is part of the tag dump system. Time delay relay K38 is related to the dump system per my prints. The fuse should be on the mastered circuit in the lower load center in the front of the bus just above and left (facing the front of the bus) from the clippard valves noted above. The relay is probably up near the main power connection point in the lower load center just in front of the pilot.

[patticake]

Jim,
If I remember correctly, the dump solenoid is just below the windshield washer module,
in the front electrical panel. It is as Leroy described. It also sits vertically.

[Jim Barone]

Thanks to all for the advice...Took the coach in to a local over the road truck shop on friday. As I was explaning to the mechanic how to dump the suspension from the dashboard I activated the tag axel dump switch and the bags dumped..Then dumped all the bags successfully...pumped them up and went through this process 5 times all successfully...mechanic went under the coach and said that the wire to the tag axel dump valve was not connected tightly..while under he drained all of the air tanks..no water or crud..checked the antifreeze levels in the main and genset...$41.00 and I'm on my way..It's really cold here about 10 degrees..we are leaving right after Christmas for Thomasville Georgia..visiting relatives is one thing..cold weather and moving to warmer climes is way more important..Thanks again for all of your help..Jim Barone fulltiming in a 1991 WBWL currently in western Ky

[Dieselbird01]

For what it’s worth. My 84 ½ PT-36 owner’s manual had the following caution: To avoid placing excessive loading on the tag axle, dump tag before dumping suspension system (front and rear axles). Pressurize suspension before tag axle. That’s the way I dumped and re-filled the air suspension on the 84 ½ for the 8 years or so that I owned it.

For the first 9 months that I owned my 91 Bird I dumped and re-filled the air suspension using the tag dump and suspension dump switches just like I used to do on my 84 ½. While at the Bird’s nest a few weeks ago I mentioned to Jessie Gibson in technical support, how much longer it took for the rear of my 91 to raise to ride height compared to my 84 ½. I explained that I was dumping and filling the suspension the same way I had always done on my 84 ½. Jessie told me that on my 91 the main suspension dump switch controls the front, rear and tag axle air suspension simultaneously and that the tag axle is supposed to assist in lifting the coach to ride height. He said that the only time I need to use the tag dump switch on my 91 is to let the air out of the tag axle air bags for maneuvering or extra traction. He said that dumping and filling my 91 with just the main suspension dump switch would not put any excessive load on my tag axle. After reading my owners manual a little more carefully I found that it said basically the same thing that Jessie said. I tried it and the tag axle suspension does indeed dump and re-fill when using just the main suspension dump switch - the tag pressure gauge verifies this. I have since been using just the main suspension dump switch to dump all of the air bags at the same time and then using the main suspension switch to re-fill them all at the same time. The whole coach raises to ride height much quicker now. I don’t know when they tied the tag dump operation in with the main suspension dump or which models work like this but some of you may want to re-check your owner’s manuals to see if you really even need to be using the tag dump switch for normal dumping and filling of the suspension air bags.

[mbrund]

Originally Posted by Dieselbird01

For what it’s worth. My 84 ½ PT-36 owner’s manual had the following caution: To avoid placing excessive loading on the tag axle, dump tag before dumping suspension system (front and rear axles). Pressurize suspension before tag axle. That’s the way I dumped and re-filled the air suspension on the 84 ½ for the 8 years or so that I owned it.

For the first 9 months that I owned my 91 Bird I dumped and re-filled the air suspension using the tag dump and suspension dump switches just like I used to do on my 84 ½. While at the Bird’s nest a few weeks ago I mentioned to Jessie Gibson in technical support, how much longer it took for the rear of my 91 to raise to ride height compared to my 84 ½. I explained that I was dumping and filling the suspension the same way I had always done on my 84 ½. Jessie told me that on my 91 the main suspension dump switch controls the front, rear and tag axle air suspension simultaneously and that the tag axle is supposed to assist in lifting the coach to ride height. He said that the only time I need to use the tag dump switch on my 91 is to let the air out of the tag axle air bags for maneuvering or extra traction. He said that dumping and filling my 91 with just the main suspension dump switch would not put any excessive load on my tag axle. After reading my owners manual a little more carefully I found that it said basically the same thing that Jessie said. I tried it and the tag axle suspension does indeed dump and re-fill when using just the main suspension dump switch - the tag pressure gauge verifies this. I have since been using just the main suspension dump switch to dump all of the air bags at the same time and then using the main suspension switch to re-fill them all at the same time. The whole coach raises to ride height much quicker now. I don’t know when they tied the tag dump operation in with the main suspension dump or which models work like this but some of you may want to re-check your owner’s manuals to see if you really even need to be using the tag dump switch for normal dumping and filling of the suspension air bags.

I noticed the same thing on my '92. I was always told by other Wanderlodge owners to air up just like you stated for the '84. But when I did that, the back end never comes up until I engage the tag axle dump switch. When I talked to others they said something had to be wrong with my coach. So glad to hear that it is working as it is suppose to work. I have always waited until my AIR pressure gauge got to around 100 and then flipped the main dump switch to air up the suspension. Then when I detect that the front axle was aired up I would flip the tag. So now I will leave the tag alone and just flip the main from now on unless I need to dump the tag for tight turns.

Thanks for info.