Volvo Air Tank Woes

RandyA · November 10, 2021

Yesterday I discovered a leak in the sides of both the front and middle air tanks on my 2004 VNL670. This is a spot where dirt and battery acid can collect between the tanks - it is also difficult to clean out trash in that area. The truck could still build 120 psi but a pin hole leak can become larger at any time depending of how bad the surrounding metal is. Last night I checked on-line junk yards and found prices ranging from $125 to $225 per tank plus shipping. Today I went out to our local heavy truck wrecking and recycling yard (Eubanks Truck Service) and located a chassis with 3 nice looking tanks. They removed them along with the battery tray and loaded them for $150. After I got home I removed the battery tray and pressure washed them - only light surface rust in a few spots. Tanks are solid and have all hose fittings. Product and price wise I feel lucky.

Tomorrow I hope to remove the old leaky tanks and replace them. I do have help as I am not suppose to be lifting the batteries. I haven't said much about it but they discovered prostate cancer this summer and I had the prostate removed October 22. No cancer in the bone and healing is going good - if I just could control my pee. Anyway, I am still under weight lifting restrictions. I just pray that all the hose connections seal and don't leak. That is the PIA I am worried about. Anyway, why the post? Well, it is a warning for Volvo owners - especially those with older trucks - to keep the gaps between the tanks clean and painted. Mine had about 1/16 inch or less between the tanks. Easy for dirt and moisture, even battery acid from a bad battery to end up there and eat into the tanks. The parts under the battery box are the least accessible - that's where my leak occurred.

rickeieio · November 10, 2021

Good write-up Randy, as usual. Sorry to hear of your health issues, but glad you caught it when you did.

I'll add that fuel tanks can suffer too. I had a hanger strap just a wee bit loose and road grit caused a little seepage. I had a patch put on the tank and installed all new straps. BTW, this was on a 2000 Mack CH, but trucks is trucks.

lappir · November 10, 2021

Thanks for the info. Best wishes for a complete recovery as soon as humanly possible.

Rod

Sculptor · November 10, 2021

Sorry you and your family are going thru this. Glad you are doing well.

It’s hard to force yourself to let that help do the lifting, just let it happen.

chief916 · November 10, 2021

Sorry to hear about your medical. Take care of yourself and do as your Doctor says.

RandyA · November 11, 2021

I wish I could say that today’s experience of exchanging air tanks on my Volvo was “fun”. Actually, it was more like a trip through a Halloween Spook House. If replacing air tanks are in your future – read on. If not, skip this dribble and go enjoy a cold beer.

I started at 10:30 this morning. The front wheels were run up on a set of solid 8” ramps. The driver side fairing was removed along with the battery hold down brackets. The battery was disconnected – the front negative buss first then the positive (rear) second. All the negative ring terminals were marked with a black zip tie and the positive with a red zip tie. I did not think of my aux batteries in the back or check the battery selection switch. Thus, I was surprised when the positive cable hit the frame and a shower of sparks ensued. Needless to say I put the battery selector in OFF.

The battery tray was in bad shape with several holes rusted through. Fortunately, when I purchased the replacement tanks they were still attached to the steps which included the battery tray and washer fluid tank. I decided to replace the battery tray. To do this I needed to go ahead and drop the air tanks – a process normally accomplished by removing twelve 15mm nuts. Unfortunately for me, eight of the 12 nuts were rusted too badly to remove with a wrench. Out came the 4-1/2” angle grinder with a cut-off wheel. I cut off the eight remaining nuts and the tanks dropped off. The 4 nuts on the back that held the windshield washer bracket in place were also rusted to the point that they had to be cut. With this finished I was able to put the newer, un-rusted battery tray in the framework. I had to use 3/8” SAE nuts and bolts as I did not have metric hardware.

My help arrived and we began to tackle the air tanks. Getting the hoses out of the fittings proved to be a challenge. We ended up grinding a flat on the bottom of each brass 90 degree angle fitting so that some adjustable jaw pliers could grip the bottom of the fitting and pull down the collar on the fitting. With a lot of tugging the air lines came out. Now, it is important to point out that my tanks are vintage 2004 and my replacement tanks were from a 2012 truck. The air lines used on the 2004 were a combination of 19mm OD and 16mm OD. The lines on the 2012 tanks were all 16mm OD. But I didn’t know this and didn’t think to check. I assumed – and you know what happens when you assume. We had to remove the air line fittings from both sets of tanks and swap them out to match up to the truck lines. We lifted the new tanks in place and bolted them to the battery bracket and proceeded to install the truck air lines into the tank fittings. If I remember correctly there were a total of 12 lines for the three tanks.

It was now getting dark – we had been at it 7 hours and were not finished. Tomorrow I will install the batteries, wire them up, start the truck and see if I have any leaks. Oh how I pray I don’t! Replacing air tanks, especially on a rusty truck, is an all day shove and grunt full day job that requires 2 people. I still have a ½ day of work and clean-up left. – that is providing I don’t have any hose to fitting leaks. No, it wasn’t fun. Old tank #3 is rusted but is not leaking. I also have a spare windshield washer tank. If any one needs them give me a hollar.

Edited November 11, 2021 by RandyA

rickeieio · November 11, 2021

Thanks Randy. As always, your post content is both informative and entertaining. Next time, try using heat to release rusty hardware, so you can re-use it.

RandyA · November 11, 2021

Yes heat works. For these nuts the heat would have had to be a cutting torch. The rust on the nuts was so bad the nuts themselves had rusted so they would not hold in a socket or wrench - the flats were gone and the nuts were basically round. The hardware that I did not cut was rusted so bad I was afraid to reuse it. Rick, they were way beyond just being rusty.

rickeieio · November 11, 2021

Randy, it sounds like you didn't even have a good reason to try to save anything. We had the same issues when changing parts a few times. Destroy and replace.........with anti-seize.

RandyA · November 12, 2021

Rick, I should have made pictures. Think of an unpainted piece of wood destroyed by termites, weather rot, ants, carpenter bees and years of neglect. That would be these fasteners. I am the king of saving things, too many things in fact. This has been a good truck, one owner, one driver and regular maintenance before I bought it. But, it was a contract US Mail hauler that continually ran from one end of I-95 to the other in sun, rain, sleet, snow and SALT for six years and 700 thousand miles and probably never got an undercarriage wash. If I ever buy another truck it will come from Arizona. From day one of my ownership any small body parts fastener between 10mm and 15mm that was exposed to salt would either break in two or strip out when removing. No amount of PB Blaster, heat, or even homage to the Angel of nuts and bolts would help. Those that did survive removal were cleaned in a bath of Muratic Acid or put in a rock tumbler for reuse. At first, I bought black oxide metric replacements for broken bolts. I coated them with Anti-Sieze or Fluid Film. I eventually I started buying grade 5 hardware by the pound at Tractor Supply and keeping them in bins - especially 1/4", 5/16", and 3/8" size - all SAE not metric. What I didn't save was replaced. Hey, all those rusted parts were replaced with new or cleaned and repainted unrusted parts. I shouldn't have to worry with them again!

BTW, like Godzilla, the beast came to life again today with NO air leaks in the tanks or fittings. That may have put a lot of bruises on my arms and dirt in my face and hair but I have a big grin on my face. We did it - and just in time to head for sunny and warmer Florida for the winter!