Losing prime, fuel drip at pump MC7

Dlsnow · June 01, 2017, 08:51:42 AM

Bus sat in storage for 2 years. It is losing prime every day.
Previously it lost prime once in the last 5 years.

It looked like the fuel drip was at the fuel pump to motor (3 bolts) but after replacing the gasket there it is clear that the drip is coming from the pump itself.

I am taking g that apart today for I section but wanted to know if anyone is familiar with this issue.

TomC · June 01, 2017, 08:59:08 AM

Detroit fuel pumps are not very expensive. I would buy a new one. Good Luck, TomC

luvrbus · June 01, 2017, 09:05:55 AM

Those pumps have 2 seals when it leaks it leaks to the outside where you can see it, just buy a rebuilt pump the end plates are probably worn now and just replacing the seal you will be low on fuel pressure

chessie4905 · June 01, 2017, 10:46:14 AM

While you are at it, you might as well replace the drive ear/s. They are cheap. Pumps are suprisingly cheap.

Iceni John · June 01, 2017, 12:51:21 PM

Should a fuel pump and its drive be in one's box of spare parts? How easy is it to change on the road? My engine has 277,000 miles - how long do fuel pumps typically last?

John

luvrbus · June 01, 2017, 01:23:28 PM

John, I carried the drive yoke they go bad the square shaft it will round out the yoke,I never carried the pump because NAPA can get one overnight but they don't sell the yoke

Dlsnow · June 01, 2017, 05:51:24 PM

Definitely leaking at the weep hole. The fork square hole looks good.
Ordering a new one and the gasket tomorrow.

Geoff · June 02, 2017, 06:52:32 AM

Quote from: Dlsnow on June 01, 2017, 05:51:24 PM
Definitely leaking at the weep hole. The fork square hole looks good.
Ordering a new one and the gasket tomorrow.

I'll buy your core. I have the tools to rebuild them.

P.M. me.

--Geoff

Dlsnow · June 02, 2017, 08:17:53 AM

Sorry Geoff - I selected a rebuild and need to return the core to get the 60$ back.

luvrbus · June 02, 2017, 11:04:48 AM

Geoff, you need cores I have a bucket full.The only ones I keep are the high volume pumps from the 8v92 DEDC and only because they work on a 60 series

Geoff · June 03, 2017, 03:32:37 PM

Thanks, Cliff. I'll let you know next time I go through Kingman.

--Geoff

Dlsnow · June 08, 2017, 05:28:30 AM

I have the new pump.
Going to put it on and i am confused.
There are three holes on the side and i only recieved two screws to plug the holes.

I am taking the old one off now so i may answer my own question here.

Geoff · June 08, 2017, 05:36:51 AM

Quote from: Dlsnow on June 08, 2017, 05:28:30 AM
I have the new pump.
Going to put it on and i am confused.
There are three holes on the side and i only recieved two screws to plug the holes.

I am taking the old one off now so i may answer my own question here.

You only plug the two top holes, the third hole is left open for leaks or pressure relief. You should not plug all three!

--Geoff