john510

Have a 91 Mack RD with a 300 E6 motor in It and it started to develop a slight vibration when idling and running in the motor, I checked the engine mounts , they are good and changed fuel filters and air filter. Any ideas? Could it be injectors has around 350 k on it..

tried jiggling the turn signal back and forth , nothing, but I noticed if I JAB on the brake pedal HARD or the hand valve the brake lights work, but if I just do it like normal they will not come on.. I checked the air flow at the switch and it blows fine..?? got me puzzled. I even replaced the new switch to see if that was it but nothing..

Have a 1995 CH Tractor and the brake lights are Not coming on sometimes, I replaced the switch by the pedal but still it appears to be random regardless if I try the Hand brake or even pull my parking brake out the lights may come on or not.. Kind a like they are getting power some of the time. I all so replaced the relay fuse for the brakes but that didn't seem to solve the problem either. Suggestions on hunting down the problem is there any more air switches to supply the electrical in the engine side or under the dash?

I have a 1995 Mack CH model tractor with an E7 300 Engine in it. Lately When I went to start it when the engine is cooled off it will sound like it missing and blowing some smoke. Yes it sound like its missing, after it warms up for 10 -15 minutes it begins to run fine and no smoke but after running for 5-10 minutes an Orange light on my dash comes on saying “Electrical Malfunction” the truck does this after it cools down for about 1 hour. If I start it and shut it down and restart it quickly there is no miss or smoke? What is your opinion on what could this be? I have a feeling it may be a injector but want to make sure?

Replacing the two hoses along with expansion block on the ac system of a 1997 ch613 and the new hose Mack trying to supply me is turned the opposite direction so the switch that screws in to the line by the expansion block will not fit.. does any one else have this problem or can you supply a picture of yours? this picture shows a generic one the blue arrow points to the line that has a switch on the end..Oh one other thing I have 2 of these pressure switches one on the bottle up from and this one on the line why 2 of them?

I have a 1995 ch 613 model with an air conditioner leak in it and put florescent air conditioner dye int he system and charged it. It works fine but slowly leaks out after 4-6 days , after looking for the leak I seen some of the dye on top of two line against the firewall as indicated by the arrows in the picture. It looks as if the leak may be coming form the inside of the cab by the core but not able to see and of the dye inside since its so tightly sealed. I removed the inside cover exposing the heater and air conditioner core and still see no dye. I think it may be where the connection is on the back side by the firewall but having difficulty removing the air duct pipe that is some how attached up top in the dash, the lower half is loose but something is holding it up top and I don't want to damage anything, any help on this would be greatly appreciated.

I just noticed the dryer unit is before the expansion block? should it not be after it comes from the firewall and before the pump?

thank you for all your help..

When the system was converted to R-134A from R-12, was it flushed? I dont recall Was the condenser removed from the truck and flushed independently? I dont think it was. Was the receiver/dryer replaced? Yes it was and and the newer style pump -----------------------------I plan on buying a new condensor I think this one has little tomuch wear on it lots of fins bent looks like its ready for another. While at it I will get a new reciever dryer. Any sugestions on the pump to insure it still functions properly? I take it that expansion valve is the block and can be cleaned in solvent and replaced. you mention the evaporator, where is that? what other solvents can i clean the system with?

Hve a 91 RD686 Mack Dump and developing a problem with the AIr.. It was changed to the 134a system while back by Mack and worked so so ever since but want to get prepared to maybe make it work little better .. seems to cycle a lot and not as cold. I did a vac of the system and reloaded it and seems better but it almost as if its not at it full potential I've included some pics of the compressor , dryer, switch on the dryer but where is the orifice tube at? is it in this block going into the firewall? How often should the compressor turn on for then off for? I do have the gauges , vac and tools to fix it..