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HDT air leaks


Padraic
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In the process, of restart my 1988 truck after 6 years of storage. There was a rather big air leak within the dash shown in the attached picture. I can feel air rush out in the area and wiggle the tube can increase or decrease the air feel. From the internet research, "Rescue tape"  may work for a short-term fix. Anyone use this tape before, sound like a good thing in the toolbox. 

HDT has a lot of air leak, I remembered my truck had slow leak 10 years ago. It never holds enough pressure for 2 days resting and less when it's aging. Usually, when the engine started, the pressure build up to 120 PSI. This time, it never passed 65 PSI and alarm go off when using the brake. So could it be the compressor going out? Will find out more after this leak gets patch.

Apparently, there are tons of air hose in the dash. All are connected to a push-in connector. Aging is not a good thing for plastic tubing, I guess. 

Anyone know what this red tube function? I vaguely remember years ago that someone has a color code function of the air tube. The label on the tube seems to be "C1R2" in some of my picture. I will confirm that code again. More research is needed.

Have you guys dealt with compressor issue and air leak behind the dash? What is your experience with the repair shop and do it yourself? Thanks.

Air leak.jpg

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  I think rescue tape has no place for airlines on your truck. 

 

 Next if your fitting that is leaking is clean where the oring is then you can just replace the oring. As was stated before cut the old line back enough to have the proper shape airline. Apply sone pure silicone for lubrication before assembly.

 I have removed the collet that was in not such good shape, but the area that the oring sits in is good and installed a new oring and a good collet. I have a collection of fittings from not knowing one can remove the oring and replace it fairly easy.

 

 So now I can use parts out of a spare fitting and fix one on the truck. I sat once for a few days waiting to get a tee. Yea I did not think of changing the oring then. Someone on this forum mentioned it so now I carry a box of O'rings in the truck.

 

 If you do not have a Whisper air leak detector. You may want to get one for your leak detection subject.

 

 

 You are not allow to use any bad words on your project,.   Vern

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Great feedback. I like to replace it if it is easy for DIY. I just needed it air up to run to a shop for PM work and check the air system after this happening. The truck is in the storage yard. But I like DIY if time allows.

Sound like O-ring in the connector is replaceable which is news to me. I suppose I can get the O-Ring from the Volvo dealer. I need to figure out how to work the connector to release the tubing. I am sure it become easy after some practice. Tight space is a concern and the aging tubing.

rickeieio, what is the title of the other thread for more information or I can search. 

on edit: Search "air leak" found a lot of threads. 

Thanks 

Edited by Padraic
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A slim pointy instrument, a flashlight, good eyes, some spray silicone lube(as per Vern) and a little patience and you'll be rewarded.

The leak I had yesterday totally baffled the Whisper.  It was in the junction block on the firewall, and I had ghost noise everywhere.  A spritz with the children's bubble soap revealed it.

Someone recently re-posted the part numbers for the rings and colletts.  Find them at either your Volvo or Mack dealer.

Edited by rickeieio
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 Stop by a Napa or maybe Oreily s auto parts. Buy a fitting that is the size you need. Pull on the loose end and pull it out. You may need a pair of pliers, or side cutters. But that piece should pull out easily. Then you will understand how they work.

 I bought a box of auto air conditioning O'rings for a steady supply.

 

  Have fun ,.  Vern

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7 hours ago, rickeieio said:

A slim pointy instrument, a flashlight, good eyes, some spray silicone lube(as per Vern) and a little patience and you'll be rewarded.

The leak I had yesterday totally baffled the Whisper.  It was in the junction block on the firewall, and I had ghost noise everywhere.  A spritz with the children's bubble soap revealed it.

Someone recently re-posted the part numbers for the rings and colletts.  Find them at either your Volvo or Mack dealer.

Really, good eyes.

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On 12/23/2017 at 2:18 PM, rickeieio said:

A slim pointy instrument, a flashlight, good eyes, some spray silicone lube(as per Vern) and a little patience and you'll be rewarded.

The leak I had yesterday totally baffled the Whisper.  It was in the junction block on the firewall, and I had ghost noise everywhere.  A spritz with the children's bubble soap revealed it.

Someone recently re-posted the part numbers for the rings and colletts.  Find them at either your Volvo or Mack dealer.

Can these items be used to fix a leak coming from the yellow service brake nob?  Sometime s when I pull the nob out alot of air starts hissing out around the nob and sometimes if I wiggle it just right it will stop.

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14 minutes ago, chief916 said:

Can these items be used to fix a leak coming from the yellow service brake nob?  Sometime s when I pull the nob out alot of air starts hissing out around the nob and sometimes if I wiggle it just right it will stop.

You could try but sounds like you may have to replace the valve itself.  They do make kits to rebuild that valve and it is really not that hard.  I rebuilt mine as a spare.  Kit with new O rings about $30.  Just be sure if you’re taking it apart go slow, take pictures at each step, and be sure you know where and how each part goes back in. I had already bought a new dash valve so I just put it in instead of the rebuild.  Get some food grade silicon lubricant to lightly grease the rings.

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4 hours ago, SuiteSuccess said:

You could try but sounds like you may have to replace the valve itself.  They do make kits to rebuild that valve and it is really not that hard.  I rebuilt mine as a spare.  Kit with new O rings about $30.  Just be sure if you’re taking it apart go slow, take pictures at each step, and be sure you know where and how each part goes back in. I had already bought a new dash valve so I just put it in instead of the rebuild.  Get some food grade silicon lubricant to lightly grease the rings.

Thank you for this info.  Could you tell me where you bought the new valve from and what you paid for it?  I've heard that this valve can run upwards of $400.00.  because it's a Volvo only supplied product.

V/R

Ben

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I bought mine at Truck Pro which is a truck parts house. There should be a part # on your valve and you can try different places including eBay. Mine was $250. The valve itself is not Volvo but may be other vender like Meritor or other.  Brad in post above found his at findit parts 

 

Edited by SuiteSuccess
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2 hours ago, SuiteSuccess said:

I bought mine at Truck Pro which is a truck parts house. There should be a part # on your valve and you can try different places including eBay. Mine was $250. The valve itself is not Volvo but may be other vender like Meritor or other.  Brad in post above found his at findit parts 

 

Thank you sir.

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1 hour ago, dennisvr said:

Thinking that I may need one of these valves, I did a search with the PNs listed in the above posts and came up with this site which has them for $219.00
https://www.anythingtruck.com/product/070-KN20619.html

This looks promising.  Need a day or so to get back into the dash and check the numbers.  Thank you.

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  • 3 weeks later...

Thanks, everyone, I got a T-Push in replacement and put it in, more leaks from the push-in Parking and Trailer valves. So hard to tell the replacement did a good job. I didn't use silicon and didn't trim the end. But the dash is open, so I can easy to recheck and re-do. I started another thread "Push-in Parking and Trailer valves" will update the progress of that piece.

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The progress has been slow, partly due to the East Coast being frozen.

I used a needle and a gripping tool, pull the air tube connector collar off from the push-in-connector. The operation was easier than I thought.  

Below is a picture of the back side truck/trailer air valve showing the old O-Ring. The old rings were in bad shape, one really bad and the others fell apart in taking them out.

Local Volvo Dealer doesn't stock O-ring, Google-searches found and ordered from a shop at Minnesota.  

Do you use silicone grease on the new O-Ring?

O-Ring-1.jpg

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We just bought a small stockpile of the various size o-rings and collets from the local Volvo dealer.  When we first inquired, they said that we could get the o-rings but they could not order the collets.  When we gave them the part numbers from the other thread, the parts guy was amazed, though said that on all the part numbers, they had never stocked them or sold them.  We had to put them on a special order and they were definitely not cheap, though we were able to order them.

We are going to make up a small spares kit to keep on hand for the inevitable leaks.

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