Ambac Pump Rebuild

[Wiscopipehauler]

Anyone in here rebuild the ambac pumps on the old e6’s, or have a new/rebuilt one for sale?  Can tell mine’s getting worn out and the throttle jumping is terrible. Picture of the pump and of the good ol 85’ mh613.

[BOBWhite]

My Mh had that same problem, does it go away under load? From what I've heard governor springs are usually the culprit. Finding people that work on Ambac pumps is tough but I think there are still a few out there. Finding parts is also pretty tough.

Best of Luck

[Vladislav]

I used to pull the hand throttle up a bit incresing idle and it stopped bouncing with revs. 

Would love to hear any results of experience tinkering with Ambac E6 pump though.

[Wiscopipehauler]

12 hours ago, BOBWhite said:

My Mh had that same problem, does it go away under load? From what I've heard governor springs are usually the culprit. Finding people that work on Ambac pumps is tough but I think there are still a few out there. Finding parts is also pretty tough.

Best of Luck

Yep it goes away under load or no load at all. Trying to cruise down the road at say half throttle is the problem. Have to treat the pedal as an on-off switch

[Full Floater]

I've have fought with this issues quite a bit, I started a couple threads on it over the years.  Earlier this year I just bit the bullet and had a perfectly functioning pump rebuilt, including the gov assembly.   Most pump shops will want to go through the entire pump, instead of just rebuild the gov.   I don't necessarily say it's to make more money, but more so when they send the pump out the door, there is no chance of complaints or other issues come up shortly there after

 

Anyways, the gov springs and flyweight bushings seem to be what is worn out in them.   Apparently there used to be a spring shim kit available thru Mack or otherwise, some time ago, that would be a half asses fix that can be done without removing the pump.   This fix would be good enough for most of us.  But seems that's not an option anymore.   (If someone could come up with a kit like this again, im sure many of us would happily pay a premium for it).   And I have exhausted that search for it.   But there is still gov replacement items that pump shops seem to be able to get.

 

My rebuilt pump now functions without the "surging" that it once did.  Cost about 3k Cad.  I'm happy with my decision to have that done.  Makes driving much less stressful, and it's easier on the rest of the truck.

Yes, throttle linkages and air ride cabs can contribute to this problem.   But there is also an issue with the gov's that is likely the problem and EVERY ambac Mack I own or have driven, does it to one extent or another, depending on wear.   It's a reality that we're having to deal with.

Edited August 23 by Full Floater

[h67st]

I had mine rebuilt at Purrformance Diesel in Fredericktown Ohio, they did a great job on it. I believe Complete Diesel in Findlay does pump work as well. You could probably ship yours to them.

[terry]

Looks like he already had it rebuilt.  Terry