The European Influence Creating Havoc.

[ciw65]

Our Quantum has just returned after 3 days of much hair pulling and swearing by Mack dealer in Adelaide, me and my bosses. It went out Tuesday morning working fine after a head retorque and valve adjustment. Got to Adelaide some 200 odd km down the road and had developed a severe air leak. Driver and yard boss in adelaide determined it was from a large "ugly" valve in the chassis, left side, behind fuel tank. They ring me, yes I have seen it, and no, I have no idea what it is. They take truck to Mack dealer to be told, yes that is a load sensing valve for the rear brake circuit. (Air bag suspension). I get the phone call again asking if I had a valve or a kit in the workshop. No, never had one. Mack dealer tells them it is quite common for them to leak, do them all the time, but, we have no parts on shelf! Yeah, OK. Mack pull it apart, clean it out and determine that internally, it's stuffed, but put it back together "to get us going". Truck goes down the road 5 minutes and completely dumps contents of air system. I get phone call. "Ok, and where is the air leak" I ask. "Everywhere" was the reply. Nothing like being precise huh. Seems every relay valve (6 in total just on the rear end) and a few other assorted valves around the back end were leaking air. I ring Mack trucks trying to translate nontechnical irate driver speak into something coherent. Mack send breakdown van out. 2 hours later I get a call again, from Mack this time, and I quote " We have no bloody idea what's wrong". I said, " I do, it won't hold f#*%in air!!!!!!". We agree on this point. 2 days later (today) they figure out that a spring brake chamber is bypassing air internally, so therefore is upsetting the air system, in conjunction with this load sensing brake valve thing (still got no idea what THAT is) that isn't working properly, so the air is leaking out everywhere. Solution, change brake chamber, air leaks stop.

WARNING!!!! Stay away from ANY truck that has any european plumbing in it.

This is just another example of what happens when Europeans get their horrible little fingers on a normal truck. Die Volvo DIE!

PS Anyone know where I can get a truck burnt on the cheap??

Edited March 14, 2008 by AusChris

[ThaddeusW]

I have looked over European air systems and they do have a very different setup but the basics are the same. Thaey even have a little less plumbing then we do and the addition of pressure test connectors to quickly and easily test air pressure in the various circuits. The load sensing valve you mentioned adjusts the air pressure to the brakes depending on the load, more weight more air pressure. Wabco, Knorr, and Haldex make them for the Euro market.

[ciw65]

Yes Thaddeus they are certainly different. I have now got my hands on a list of valves on this Quantum. 3 pages worth. What a nightmare. ABS system is basically same as most others, except the ABS computer is 12 volt, and the modulating valves are 24 volt! Then we have the collection of sensing valves for anything you can think of, pilot relay valves to activate relay valves to activate a pair of brake units on one axle. Load equalizing valve for the suspension, the aforementioned load sensing valve and numerous quick release valves. Personally I think a few less pilot valves and a bit more 1/2" and 3/8" air line would do exactly the same job. Most of the air line in the chassis is 6mm and 8mm. Oh yes, almost forgot, the air fittings are all single use, push in type with swivel. Most useless when trying to change valves.

[ducky698]

I have had a GTE45 foot trailer do that! more than once, it wont release brakes and just dumps its air, i have re\leased the maxis by hand and come down greenmount hill at 62 ton twice ewith no brakes on the B trailer cause of it. the thing has spent countless hours at the work shop trying to determine the problem. it turned out been a maxi up to mischef.

when your 13hours from home the choice was simple, loose the brakes and think ahead when stopping.

this same trailer has also broken an axle twice, and second time it all most flipped the trailer.

Grant

[ciw65]

Ah yes, the infamous "Greenmount". With a "normal" air system it is usually pretty easy to pick up a bypassing booster as air leaks out the exhaust port on a relay valve or quick release valve on the service brake circuit. But now in SA at least, rated trailers have to have pilot relay valves, and QR valves everywhere. Makes it interesting when you have a double hooked up and the trailers are dumping air out the exhaust ports on BOTH pilot relay valves. That one took some working out. But these quantums are in a league of their own when it comes to plumbing, and what makes it really hard is that the air lines are all black, basically the same sizes (6, 8 or 12mm) and bundled together tightly in the chassis, so if you are trying to follow a line from a valve, you have to cut cable ties, undo brackets, etc. to find where it goes to (usually another queer looking valve). And no, Mack don't have a schematic of the air system. As the foreman at Mack in Adelaide said to our driver last friday " I don't want to see you or this truck again!". Pretty poor attitude, but I can understand why. So I am off to Adelaide tuesday to have words with the SA manager and the workshop manager to basically tell them that while it has their brand on it, it's their problem too!!

[ThaddeusW]

Chris,

This is a Euro brake diagram form a Knorr PDF I snagged from their site a while back. It only showes a single axle tractor but I am sure a tandem is close to this diagram.

[ciw65]

Thanks for that thaddeus. Is the knorr ABS diagram. Very handy as we have volvos in our fleet too. I am trying to "break" into the Renault site currently to try to get a schematic for the quantum, because, guess what, Good Friday, and the phone rings. More air leaks on the nightmare. Much appreciate that diagram.

[ThaddeusW]

Hey Chris,

If its possible to get the Quantum cab tilted and snap a few pictures of the engine bay? Would appreciate it.

[ciw65]

Yep can do that for you Thaddeus. Won't be til tuesday though. I finally got an air leak on this thing that was easy. Leaky QR valve on the rear drive. 10 minute job. Something has to go my way sometimes. Pretty average looking engine bay til you look at it from underneath. LOL. Just an EA7-470 stuffed into a european (Renault) chassis. Will post pics tues night (local time) hopefully.

Some pics of this things air system rear of the gearbox.

[ciw65]

Update: Saturday, 5th April, 2008. Last weekend (saturday), replaced air dryer unit with generic Wabco unit. Sunday called in as truck not building up air. Temp fix til monday. Monday fitted D2 governor valve to compressor ( yep down there in the chassis). Builds up air like a new one now. Driver happy chappy.

Friday 4th April 2008: Driver rings up saying R/H front cab air bag leaking. Do the ring around and find (as usual) genuine only, AUD175.00 PLUS 10% GST. Gotta get one.

Today, 5th April 2008. In to work when truck gets back to fit cab air bag. Straightforward job as only located on the bottom with 2 "pins" and push in fitting for air line. 15 mins and I'll be outta here. WRONG! While jacking cab up, hydraulic line breaks at rear cab mount locks. Great cab is up 6 inches with weight still on front air bags. Get porta power and stuff around grovelling under this bucket trying to find a spot to jack the cab. Remember it's R/H drive so all the steering gear and associated plumbing is on R/H side. 45 min later job is done. Try to jack cab down - nup no go. Blown line just vents fluid. Much cursing of French design idiots. Suicide decision made. Crack hydraulic line on Cab Ram. CRASH Cab is down. Bugga - didn't break. Oh well. There is still the burning option.

And you wonder why I hate this thing???!!!!