Mack truck starter
If you have a pre-engauge and don't hear the clunk then air isn't getting to the pre-engage cylinder or the pre-engage cylinder is stuck. If its the pre-engage type, what Olive said about hearing the clunk and then the starter motor spinning a second later is a good indicator. First see which of the two styles of motor you have. It sounds as if you aren't getting air to the main starter valve at all. I re-read your post and I missed something from before. I have lubricated starter at starter end would lubricating from tank help by doing valve and starter ? but on all other starts works fine what do i look for ? the starter fails when i hit start button (electric over air type ) air passes to starter but doesnt engage and spin over motor. Problem is occassionaly about 1 in 20 starts.
#MACK TRUCK STARTER FREE#
Thanks for the info - yet more free stuff for future use! It was always a little strange sounding when you would hit the button, you would hear a clunk, then a second later the main air supply would engage. I guess the first type of air starter you describe is what I must have had on some CCC garbage trucks I sold. They were like a normal type starter, just big assed! I had to replace some on some ex-Roadway trucks a few months ago. You will have to drop the starter to check and fix that problem.Įxcellent information - I have not had to fool (yet) much with air starters but I get a lot of trucks that have them. Even if the springs were shot it should at least mesh or grind, the springs makes sure it un-meshes when the engine spins up or starter shut off. If that is the case then the bendix drive assembly might be getting hung up, maybe old dry grease is making it stick. That setup has no extra hoses running to the starter motor as the spinning force makes the gears mesh. Once the engine starts it spins faster than the starter and the pinion if forced back and held by the springs.
![mack truck starter mack truck starter](https://images.truckpartsinventory.com/parts/25120/2006-Mack-E7-Starters-gBEWuiODwqDX_b.jpg)
The pinion is spring loaded and when the starter is spun up the pinion is forced into mesh against the springs with the flywheel by "unscrewing" (for lack of a better term). The pinion is on a bendix drive that works by having a thread like groove cut into the pinion shaft. The inertia system works like a car starter. If the pre-engage cylinder is shot it might be time for a re-build. I don't think that part of the starter circuit is lubricated, only the air motor. It may be a good idea to un-hook the line from the starter knob/solenoid and get some oil into the pinion cylinder. If you have the above setup then make sure the pre-engage piston is actuating the starter pinion. Once in mesh there is a valve in the starter cylinder which sends air pressure to the second line which in turn opens the main air valve that runs the air motor. The way it works is when you push the start button, the air first flows to a cylinder that forces the starter pinion into mesh with the fly wheel.
![mack truck starter mack truck starter](https://images.truckpartsinventory.com/parts/81/Mack-MP8-Starters-1xXBCRDkiXlt_b.jpg)
Pre-engaged air starters have two smaller air lines running from the front of the starter (closest to the flywheel housing), one from the starter knob in the cab(or electric over air solenoid as in your case) and the other to the main air starter valve that runs the motor.
![mack truck starter mack truck starter](https://i.ebayimg.com/images/g/v-0AAOSwNP1hnO4U/s-l300.jpg)
Which make is your Air starter, Ingersolrand? There are two types of air starters, one is called pre-engaged and the other is inertia engaged. Just rebuilt main starter air valve at tank end was very sticky when i remove plunger from valve cleaned up refaced seat end and fitted new o ring kit started a few times all good will see how it goes now will post and let you know thanks
![mack truck starter mack truck starter](http://sc04.alicdn.com/kf/HTB1HLXYKAOWBuNjSsppq6xPgpXaA.jpg)
Have been keeping starter lubed by running lube direct to starter via main line ( starter works fine ) at regular service intervals.