Rob Posted December 25, 2019 Share Posted December 25, 2019 Recently my R-612 has started making a strange noise from the engine that is gaining in intensity. Engine starts and runs fine but noise I'm hearing is kinda like a couple of marbles in a tin can sort of like shaking a glass of ice water in your hand. Sometimes more pronounced, sometimes relatively quiet. Seems to be emanating from the rear of the engine and traveling through the sheet metal of the firewall/cowl of the cab. I took a sounding rod after it listening to both the drive coupling, and power steering pump drive with nothing abnormal noted. Easy to hear normal gear train noise but that's with any engine. Water pump, tip turbin, and turbocharger all sound good at low, and medium idle so kinda lost. The air compressor, (Midland EL-13111) has started to occasionally stop unloading at operating speed when driving. I'll hear the pressure relief in the wet tank popping at highway speed. I replaced the D2 governor with a known good shop spare and the problem is so intermittent, it didn't show up again for about a month then same thing again. I'm not sure if both problems are related or not? Regardless, I spoke with a gent at Rebuilder's Enterprises up in Bridgeview, IL yesterday and he tells me if I bring the air compressor in first thing on Monday morning, I can pick it back up fully rebuilt just after lunch so may do that. They also have remanned units on the shelf. I might send the power steering pump, (looks to be a Vicker's V-10 series) in at the same time to be resealed as there is a seepage leak although I expect that is worn hoses or sealing rings aged out. I was going to run new hoses anyway as the braiding is falling apart on the outer surface. I've used them for a vendor in the past on an old Midland compressor for my A-40 and they did a good job. Can't remember the numbers on it, (21 years ago) but it had external rocker type arms for the unloaders. Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/ Share on other sites More sharing options...
eddeere Posted December 25, 2019 Share Posted December 25, 2019 Let us know what fixes the noise. Quote Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-438827 Share on other sites More sharing options...
Rob Posted December 25, 2019 Author Share Posted December 25, 2019 21 minutes ago, eddeere said: Let us know what fixes the noise. Chasing same thing? Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-438831 Share on other sites More sharing options...
theakerstwo Posted December 25, 2019 Share Posted December 25, 2019 Rob as for as the compressor goes first if its got a dryer then pinch off the signal line to the dryer and if its better then its the purge valve on the dryer.If not then get you a field service kit and replace the unloader in the comp.Its on top and easy to do.On the noise i would take the belts off and run it and see if its not a brg in the water pump or alter.Also it its got a jake brake look at the flat return springs in the jake heads.If your hearing it more in a hard pull then think of a broken head bolt or blowed head gasket. 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-438837 Share on other sites More sharing options...
Rob Posted December 25, 2019 Author Share Posted December 25, 2019 1 hour ago, theakerstwo said: Rob as for as the compressor goes first if its got a dryer then pinch off the signal line to the dryer and if its better then its the purge valve on the dryer.If not then get you a field service kit and replace the unloader in the comp.Its on top and easy to do.On the noise i would take the belts off and run it and see if its not a brg in the water pump or alter.Also it its got a jake brake look at the flat return springs in the jake heads.If your hearing it more in a hard pull then think of a broken head bolt or blowed head gasket. Hi Glenn, thanks for jumping in; I don't have a dryer on this truck. Have one for it in the cabinet but too lazy to install I guess..... I have replaced the unloaders in the compressor head but it's been over a year. They were sticking routinely and the relief was popping at engine idle. That ceased immediately and this problem only presents itself at highway speeds now. Probably the unloaders again and I'll order another kit to service the head. I've not removed the belts or any ancillary drive parts from the equation yet; good tip and I'll follow up on it. Just really noticed it a few weeks ago and it's not consistent. The noise is just when bringing the engine up from low idle. I don't really hear it when driving due to cab noise. Not really a quiet truck at all as most of the sound insulator padding is deteriorated; especially on the firewall interior. The engine runs smooth and starts easily and seemingly never misses a beat. I'll pull the belts as they need changed from age anyway and they're at least a dozen years old. Thanks, Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-438842 Share on other sites More sharing options...
Rob Posted December 26, 2019 Author Share Posted December 26, 2019 Found the rattle and it is the air compressor coupling where it is driven from the auxiliary shaft I believe. With a helper operating the throttle, it really gets loud through a sounding rod when the engine is brought above idle. I have pulled the belts and ordered new and although they look good, they are quite aged. Here is a quick video I shot earlier and the truck is now in the shop and the air compressor will be removed tonight or tomorrow morning. You can hear the rattle as I bring the throttle just above low idle at the start and the microphone picks it up all through the rpm range better than I can hear. However when the engine is returned to low idle, it is pronounced for a short bit also which is discernible: Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-438903 Share on other sites More sharing options...
Rob Posted December 27, 2019 Author Share Posted December 27, 2019 (edited) Pulled the compressor this evening and the nut retaining the drive hub for the compressor was loose. No foldover locking flange present behind the nut so it backed off. Nothing appears to be hurt but I'll run over and pick up a new drive hub kit tomorrow as they have it on the shelf. Need to pick up some SAE100R5, (Stratoflex) hydraulic hose also as the original is brittle from age. With the cooling system drained and air compressor removed, I zip tied a plastic bag over the compressor mounting flange opening and ran the engine. The noise is gone so for now I'm holding the compressor coupling suspect. Edited December 27, 2019 by Rob 1 Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-438921 Share on other sites More sharing options...
terry Posted December 27, 2019 Share Posted December 27, 2019 good thing you caught when you did, good job of figuring that noise out! terry Quote Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-438923 Share on other sites More sharing options...
Rob Posted December 27, 2019 Author Share Posted December 27, 2019 (edited) 8 minutes ago, terry said: good thing you caught when you did, good job of figuring that noise out! terry Thanks Terry. That was a challenge for sure. Don't always know what is wrong, but always keep a close eye and ear on what changes. Had this truck long enough I feel most every rattle and squeak is known so when something outside the normal rears it's ugly head, I usually get onto it pretty quick. Edited December 27, 2019 by Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-438924 Share on other sites More sharing options...
Rob Posted December 27, 2019 Author Share Posted December 27, 2019 New drive gear has a lot more material on the intermeshing teeth than the former. Purchased the complete kit at Mack for $61.00 and it came with the gear, flange lock, and nut to retain the assembly together. It went right together but I need to get the hose mentioned earlier and sealing rings before buttoning it up as really don't want to do it again. Also ordered a head service kit from PAI and it will be delivered here on Monday. Mack didn't have it in stock and Fleetpride delivers where Mack does not so ordered from them. All good and off to see the grand daughters. Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-438945 Share on other sites More sharing options...
theakerstwo Posted December 27, 2019 Share Posted December 27, 2019 Dont drop the oil feed tube. 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-438953 Share on other sites More sharing options...
Rob Posted December 27, 2019 Author Share Posted December 27, 2019 Yup, that's kinda important. 1 Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-438958 Share on other sites More sharing options...
Quickfarms Posted December 31, 2019 Share Posted December 31, 2019 Is fleetpride a pai dealer? Quote Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-439111 Share on other sites More sharing options...
Rob Posted December 31, 2019 Author Share Posted December 31, 2019 5 hours ago, Quickfarms said: Is fleetpride a pai dealer? I don't know if all are but the one in Peoria, IL is and has been since the 1970's when it was a private owned truck parts outlet. I try to stay loyal to them but the last of the "Old Timers" are done today and retiring. It's not the same store it was when privately owned. Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-439129 Share on other sites More sharing options...
Rob Posted January 1, 2020 Author Share Posted January 1, 2020 Head service kit showed up yesterday as scheduled but I'm a bit too tired to work with it. Just going to chill for the balance tonight and get after it tomorrow. Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-439149 Share on other sites More sharing options...
Rob Posted January 3, 2020 Author Share Posted January 3, 2020 Finally found what I think is the problem with the unloading of the compressor. The rear most unloader had to be pried out of the guide and was stuck fast. I basically destroyed it by pulling it out with needle nose vise grip pliers. Don't really notice any carbon buildup in the bores and I went ahead and removed the head finding nothing really out of place. I'm going to make a wrench to remove the valve plates and then send the head through the hot tank to ensure it's clean. I think I have the correct size reamer in my box to ensure the guides are clean but will need to look. No oil or carbon in the discharge pipe to be concerned with either. The compressor is about 11 years old or so since rebuilt but not many miles or hours on it since. Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-439302 Share on other sites More sharing options...
Rob Posted January 4, 2020 Author Share Posted January 4, 2020 I found my reamer set and worked through three of them before getting a nice clean scrape from the guides of the unloaders. I do think that rear one was the culprit. With the new unloaders, and coupling assembly installed, the system seems to be much quieter and the system unloads readily when the engine is held at a steady 2000rpm. I've not driven the truck since buttoning it up but may tomorrow. So far however the engine is much quieter and that "rattle" seems to be gone. Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-439368 Share on other sites More sharing options...
Rob Posted January 6, 2020 Author Share Posted January 6, 2020 All good now. Had to adjust the D2 governor a couple of times to set pressures correct but it readily unloads properly now. Ran a steady 80mph on one of my favorite back roads and governor holds right at 120psi. Truck is pretty stable at speed too so tire balance must still be acceptable. Of course it is an R model after all so who would expect less..... 1 Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-439657 Share on other sites More sharing options...
Rob Posted January 6, 2020 Author Share Posted January 6, 2020 Noise is gone: but getting ready to clean it up: Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/60294-strange-noise/#findComment-439659 Share on other sites More sharing options...
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