water pump for a 478 with air brakes

[twarner]

I know this has been asked before, but I did not see any recent threads and NAPA claims they no longer carry one, but I need one for my L8500. Where can I purchase a water pump? Anyone have a good one?

Thanks!

Terry

The truck is our water hauler, so we will need it soon....Lol

[bigblockv6]

Do you have the bigger heavy duty water pump? If you do those are serviceable, I have a GMC Manual that mentions this. I'll look it up to see what the procedures are or you can find a local rebuilder. The smaller pumps are the same as mid 50's and early 60's Pontiac V8's good chance those are still be produced.

[tommr]

Terry use the search feature and type in 401 water pump. the 401 with air brakes is the same pump. there are part#s in that thread that you can google. you need the pump with the threaded keyed shaft. they are available. good luck. tom

[twarner]

Thanks guys! I'm checking now.

Terry

[twarner]

Here is the pump I ordered on ebay. I removed the old pump and it sure is bad.... the impeller just unbolts from the front of the water pump housing and I have the 5/8 fan stub, so the other threads and stuff on this site, I've found said this should be the 401/478 pump for me. You can also get this with a 3/4 in shaft as well.
http://www.ebay.com/itm/261726987664?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Thanks again! Terry

[tommr]

doesn't your existing pump have the threaded shaft with the notch for the key? the pump you are showing has a conventional flat flange. ebay item 261656100663 should be the one you need. tom

[twarner]

no it has the flat flange with the 5/8 shaft. The pulley and fan just bolt on with the four bolts. That's why I wanted to remove it first, before ordering anything. Now I can also say this was not the original pump!!!! After removing the pump, it had numbers on it that led me to the one ordered as well.

Terry

[twarner]

So this part Cardone 58-160 that I have ordered on ebay, I'm not holding out much luck in getting it in a timely fashion if at all. And I do need the one with the 4 bolt flange and a 5/8 pilot for the fan. So I am pleading again for all you folks with parts to have another look and see if you have one. I can't wait months for this as we use this old truck for real and depend on it. Maybe that's not a good thing as it turns out. Shame as the truck has no rust and almost no miles on it. Been in New Mexico most of it's life. 478 and a 6 speed allison auto. 43,000 lbs GVW and it might just be for sale soon.....

Terry

[tommr]

terry if you google that part # there are a bunch of guys showing this pump. cant you get one of those guys to pronto you one out. tom

[twarner]

Hi guys,

Update! over on stovebolt, one of the fellows there had a part number for a Gates pump the Amazon says they have in stock and it's new. Waiting on tracking info. All the other parts places that might show a "in stock" status come back with, we need your core to send to cardone for an overhaul. So not really in stock per se. So what I think I will do here is: Get the new one if that's real and have the old one rebuilt. I or someone will need it. That's what I'm thinking.
Terry

And Thanks everyone! If it was not for the knowledge base of folks like you out there, I would have not bought this old truck.

[tommr]

What model; Allison is in your GMC terry? tom

[twarner]

That's a great question! I have tried to figure that one out myself. I've not found any markings on it, it's a manual shift, meaning there is no electronic's.

Trans had a hyd PTO at one time as well. Here is a link to some photos:
https://www.flickr.com/photos/terry_warner/

I took these photos when I first brought Chug home.

Terry

[twarner]

Amazon came thru with the gates pump that is brand new! Arrived here today, however the fedex guy got stuck in our driveway. epic snowstorm last night and today and we are at 7800' so had to get the tractor out to get him back on our gravel drive. No problem however as It's the right pump and it's new and here.

Terry

[tommr]

glad you got it terry. truck looks awesome in the pics. thought maybe you had a later Allison it in it. tom

[turbobill]

That transmission is the MT series, probably an MT 40 or 41. It's a 6 speed, direct in sixth with locking torque converter and more than likely has a grade retarder.

[tommr]

super nice piece terry. keep it going. ive seen those MT flexplates on Ebay for the V6s. im pulling the non synchro Spicer 4 speed out of the bus in the next couple weeks. plan is an Allison 2100 5 speed auto overdrive trans. main issue will be if torque converter hub will pilot into the crank end bore. tc hub may need to be machined. will need to have a custom flexplate made. I haven't seen the late Allison on a V6 but im sure its been done. tom