jeffl1107

Hey guys, thanks for both of your comments. They will help. Yeah, sorry about that, came back and read it again before your post and realized you said, "CANT". I got everything stripped off about an hour ago. Was not that bad taking off. Got a couple of questions though for either of you. First, it must have been the original housing because there was "NO" bolt hole in top of housing. But the new one does have a threaded bolt hole. They did give me a 1/4" bracket. But, I cannot see where it would bolt onto the head. It has 3 bolt holes in the bracket. It has 2 bolt holes top to bottom and then around the middle is a portion sticking out that has 1 hole, I guess to the housing. But, the paperwork they gave me with the recall stuff on it, says that only the CH model can accept this bracket. I have an RD. Will this not work then? I got everything new. Pump, housing, bolts, gaskets, belts, etc. The new fan is metal that they gave me. And yes, I did see the report that says if this issue continues, to replace the vibration dampner. I dont know how expensive they are, but I am wondering if I should just get that also. Parts wise, and wallet wise, I can afford for this to happen again. Not only did it cost me almost $600 in parts, but I cant afford to take that hit again and more importantly losing out on work. Guys never called me back from Mack today for price, so do any of you have a guess what the harmonic balancer goes for???

Thanks for the info. Couple of questions? First, you said the the fan weight on the hub can be changed. Was wondering if you could elaborate on that. Do I get a different model or do the new fans just weigh less. And second, do you know how I would find out if my particular truck calls for that bracket. The guy at the parts place I go was kind of unsure. Thanks

Hey Everyone, Need some help here before I put a bullet in my head. I am having an issue with my water pump. Its a Tri Axle Dump 97 Mack RD688S with a E7 350. Last six of Vin is 032419 if someone has any diagrams. Ok, I drove the truck for about 1 1/2 months then my water pump went. I noticed over a period of about 2 weeks that the water temp. was reading hotter and hotter later in the day until it finally went real high and the temp light came on. So I got a replacement pump and put it on. Ok, here is my delimna. It was about 1 1/2 weeks ago that I put the new pump on. The pump mounts on 2 places. It mounts with 6 small bolts on a housing on the front of the engine. Then there are (2) 12MM bolts that screw on the drivers side of pump to the oil cooler. Well the day after I put it on, about 7 hours after hauling, the bolts had backed out enough that antifreeze started spewing out of the gap where the pump and oil cooler come together. I saw no reason why this should happen but took the bolts off and replaced the regular washers with lock washers. Went the next day and about the same amount of time as before, it starts all over again. Bolts again backed off enough that it started leaking again. I took the pump off and checked the pump. Also had a mechanic friend come over and he said pump looked perfectly fine. We cleaned it up, put new gaskets with the high temp. permatex with new gaskets. Put the lock washers back on and also added Locktite to the bolts. Again, today it happened again only this time it cracked the heck out the housing the pump bolts on. So now I have to replace the housing. The clutch fan that is on it, one of the blades has 2/3rds of it missing. I asked the mechanic if that is enough to throw it off balance and possibly be doing this, he said he highly doubts it. He also said how would it have lasted all the time without leaking before replacing it. I am going to replace it anyway. So, I am trying to figure out why those 2 bolts keep backing out. There has to be somekind of vibration that is doing it, I cant figure out what else would be doing it. Anyone have any ideas. The guy at the parts store said he thinks there should be a bracket on there but I dont have any schematics to check and see and he was not sure as the computer did not show one for my year but he thought it did have one for my year. He also told me that they did away with the small bolts that mount onto the housing. They use the same size bolts, but now they have longer bolts with a spacer. I asked if the small original bolts could have had anything to do with my problem but he said not likely since it was the 12mm bolts that were backing out. I need to get this problem fixed so I can stop losing work. Any help appreciated.

Ok thanks for the input. I am going to check the truck over this weekend to see if I can find anything. Yes, it does idle fine for a while. I normally leave the yard with the truck around 5:30am and I would say around 12 or 1 in the afternoon is when I start noticing the idle getting lower. By quitting time around 3:30 it is really low, does not kill the engine but close to it. My question is with you saying that the cab air bags might not be holding the air and is pinching the linkage to the throttle. If that was the case, why would it not have a low idle all day and just the latter part of the day?

Ok, this is the weirdest thing I have seen I have no idea what the problem could be. My truck, 96 Mack RD688S dump truck with E7 350. When the truck warms up, maybe after an hour, the idle slowly starts dropping in RPM's. By the end of the day it is really low, like almost ready to die if I dont keep it up in RPM's. But the odd thing I noticed yesterday is that it seems when I get up off the seat and exit the truck, the idle goes back to normal. It sounds normal while I am out of truck and someone was loading me. But as soon as I get back in and sit down, the idle goes back down again. What the heck could that be. I cant see how it could be something with the seats air system, but was thinking maybe something with the cab. I know it has some sort of air ride system on that and dont know if there is somekind of sensor or something. This has me totally baffled. What do you guys think???

Ok, thanks for the info Phil, I will definately check that out tomorrow morning.

Hey All, 97 Mack RD688 Dump Truck. Got in this morning around 5:30am, turned the lights on and No Headlights. All other running lights work fine. The bulbs in headlights are brand new. All fuses seem to be ok. Any idea's what it could be. I had a late day and did not get back to just after dusk. Now I need to go down there early in the morning and try and get these damn things working for tomorrow. Any help greatly appreciated.

Lost track of this post. Well I am now working but I only got the Commercial tags to run just in Jersey. Probably a very bad decision as I am not staying steady and missing out on alot of Back Loads because of it. So I am thinking of getting the Apportioned soon. But, I have now spoken with 3 different guys that have been in the business for many years and all 3 of them said they dont have an MC Authority. They said just get the Apportioned Tags with your DOT number and that is it. They said they dont have it because all they are running is Jersey and PA. I dont know how they are doing it, but they are. I will have to talk with them more about it but from what I know of, you have to get your Authority if you are running in 2 or more states that the IRP is in effect.

Feel bad for me because I still live here in South Jersey. I just brought my truck to a private place for the Smoke Test and it threw a 31. 97 Mack RD688S E7 350. Now they say I have to bring it back tomorrow so they can attempt to Detune the engine to try and get it to pass. My question is why didnt they grandfather the older trucks. They were never designed to pass the new standards. I have a few choice words for them, but I will refrain so I dont get out of hand. I have my reservations whether or not they are going to be able to get it to pass with my truck. I wish I could exempt myself as I signed up with the FMCSA to do my own Vehicle Inspections. Bunch of BULL!

Hey all, I took my truck, 97 Mack Tri axle to shop on Friday to have a Smoke Test done. I was told 2 months ago NJ lowered the points from 40 to 20 for emissions. My truck threw a 31. So I am suppose to bring it back tomorrow and they said they would try and Detune the E7 350 engine. They said they would first check to see if the fuel pump diaghram was ok. If it was, then they would have to detune it to get it to pass. My question is what do they do on the pump to get it to pass. And will it hurt the performance of the truck. Dont know much about how they do that and the guy did not really offer any explanation as to how they do it. Thanks

Ok try again.

Here's a pic.

Hey Guys, Need some help and input on a tailgate issue I have. I purchased the 97 Mack RD688 tri axle dump used. It has a 17' 6" Aluminum dump body on it. The guy I purchased it from switched the original tailgate over to a steel tailgate so he could haul concrete, stupid idea on his part with the aluminum bed. Anyway, he said he did not have the original gate anymore. The Steel gate is just a little bit smaller than the opening on the bed so I have about a 1/2" gap on either sides of the gate to the body. So, I need some input as to what I could use to close up this gap so I dont leak any material. I had a guy weld some angle iron on it. He put it along the edge on the inside of the gate. But he said he did not want to put it all the way up tight because if the gate shifted just a little when I dump a load, then I might not get it shut again. I can get where he is coming from, but that does not help my problem with still having a gap. I searched online for some sort of rubber seal or something. About 3 different patents popped up for this very thing, but no companies came up that offer something like this. I figured there has to be something like this out there, or maybe one of you guys have an idea. I thought about finding some sort of heavy rubber, maybe like the stuff they make the mud flaps out of, and screwing it on to gate so when it closes, that would close up the gaps. Any input?????

Problem solved. I am a dumb A**! I retraced my line and found out that I had the ride bag hose in the main hose port and the main hose in the ride air port. Switched them and works like a charm. DUH!

Forgot to put this up for you to see. Use this link http://www.hendrickson-intl.com/pdfs/Auxiliary_PDFs/H605.pdf Scroll down to page 12 to the HLK NSI. That is exactly how I have the system plumbed. But no where on there, or any of the other setups does it show what to do with the Yellow Exhaust inlet. Somewhere I thought I might have read that it should go to the lift springs, but how would it if the blue line goes to that. I am dumified.

Ok need your expertise one more time. I am about to bash my friggin head against the wall. I don't know if I am just a Dumb A**! or what.<br> Ok, first, my setup has no electronics, totally manual. One non-steerable lift axle Watson & Chalin 25,000lb. I went out and purchased the new HLK NSI in cab kit for the axle. It came with the push pull valve, adjustable regulator to regulate how much air is in ride bags and the guage. Both Hendrickson and the Watson & Chalin had the same inlets on the bottom, just liked the ease of the Hendrickson push pull valve better.<br> So, went to install it. All were color coded. There were no instruction that came with this kit. Guy printed me off some paper work and said that should be all I need, NOT! Put the line going from tank in the Green push in 3/8 inlet on bottom of kit. Put the Ride air bag line into the Red inlet. Put the lift bag line into the Blue inlet.<br> Here is where it all started to suck bad. Here is the site I found on line for the kit I bought, no where on that page, or any of the other setups, does it tell you what to do with the Yellow inlet which it says is the exhaust port. So started the truck up and it just spews air out of that inlet. But I don't know where to run that too. I also got two valves with the kit. One valve goes off the tank for a safety valve for the brakes. The other is the quick release valve. One IN port and Two OUT ports. The IN port is the Red line for the ride air bags. The other Two OUT ports goes to each of the two ride air bag fittings. So, where oh where does that yellow port suppose to get plumbed too??????????????????? I cannot figure it out. Please help before I have to go on major medication!

Hey Guys, Big Mac - I am running 11R24.5 on their right now, no floats, Yet. RFC - You may have something there but this is how the truck was plumbed when I bought it so I assumed it was correct. But, with how this guy took care of this truck, I would not doubt for one minute that something is F'd up on it. HK Trucking - After speaking with the guy at the parts store and threw trial and error from what I already replaced, I think what you are saying is probably the case here. I just bought the whole in cab kit, regulator, push/pull valve and guage. It also came with new style quick release valves that the guy suggested I upgrade to as they release air faster than the old style on there now. Should not take long at all to re-plumb for the new style valves. Should take me an hour or two and then, god willing, it will work. Already have several loads of crushed clam shells I will be delivering to the Port Norris area of Jersey starting on Tuesday. Cant wait to get this thing rolling.

Well I finally got all the stuff done on my truck except for one pressing issue that I need to get fixed. 97 RD688S Tri Axle Dump. The issue is my lift axle. It goes down in no time flat. But when I pull the (push/pull) valve, it takes almost 90 seconds before the lift tires start to come off the ground. With this being a Watson & Chalin non-steerable axle, that is no good. I have replaced most of the air lines to it, new push/pull valve and new quick release valves at every air bag. The only thing that I believe I have not replaced is the adjustable pressure regulator in the cab and the guage. I have adjusted the regulator in the cab anywhere from 20psi up to 85psi and it does not matter, still bleeds off the same. Someone told me there might be a screen in the system somewhere that is clogged up but I cannot figure out where that would be. Does anyone out there have any suggestions as to what might be causing this. Thanks!

Correct you are, but yes, full air pressure with parking brake in. Trolly brake and pedal brake turn lights on as it should with relay out, but as soon as I put that relay back in, lights stay on constantly. I am now, to use a big word beyond my capabilities, befuddled!

Yes, the pedal comes all the way up. There was no flickering or anything when I pulled on it or shook it. So, hear is the latest with it. I fooled around with it for a while yesterday and this is the latest. I went over to the fuse panel behind the dash on passenger side. I started pulling out the relay and I saw the lights starting to flicker. I then put it back in and stayed on again. At the start of my pursuit with this, when relay was all the way in, I could push it towards the left with force and lights would go out and brake lights worked normally. But when I let my finger off it went back to staying on. Pulled it out and they went out again. Pushed on the brake pedal worked normally. Pulled trolly brake and worked normally. Works normally with blinkers on. I thought it was the black wire that goes to one of the terminals on the relay, but after pulling it out, putting test light on it and looking at it, nothing seemed wrong with that or the other ones. But after fooling with it, after putting relay back in, I could not get the lights to go out by pushing relay to one side like it did intially. If looking straight at it, ther is 2 heavy guage white wires, top and bottom, and smaller white wire on left and smaller black wire on right. Tested all and grounds seemed good and hots seemed ok. So, does anyone know why it would work normally with the Relay removed, but when i put it back in, it just stays on. I know it cant be good to run it any length of time with no relay in it. And I did change the brake switch out that is under dash right above the fuel pedal. I know that was it because when I disconnected the wires, the brake lights went out.

Ok about at my wits end with this thing. The brake pedal does not seem to have dirt under it. Seems to be ok. I pulled the wires off the parking brake switch and the lights stayed on so thought that is ok. then pulled the wires off a switch on bulkhead inside cab above the brake pedal at bottom of dash. Lights went out. Put them back on and the brake lights went back on. So I replaced that switch and still, the lights stay on.

replaced the pressure switch and brake light is still on. I am at my wits end with this thing.