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View Full Version : New Water Pump Back or Good used one (Where can i get one?)



2628
03-10-2014, 04:19 PM
It pains me to have to post this!
Which means in my case failure.
As many of you know i replaced my water pump. (New one came with no back)
So i had to use my old one, Which had a partially eaten rusty spout (See pic below)
In which case i used my side grinder to cut the eaten part away and make the edge straight again.
Then i used my Dremel to get rid of the rest of the rust,
And make the hump better for the heater hose to go over.
All seemed great no leaks while driving the car and letting it run.
But let it sit for a day. Here comes the leak!
I put a small mirror down there and actually can see the drip.

At least if i can get a new back?
I can install the studs for the water pump like Bill suggested.
So can anyone point me where to get a new back?
Or a new good used one?
Thanks in advance!

1470

Greasy DeLorean Mechanic
03-10-2014, 04:33 PM
Is it leaking from the return line barb? (That's what the 3/4" barb is. Community commonly gets water flow backwards: Y pipe is outbound distribution, not return). If it is, easiest thing to do would be to pull out the pressed in barb, tap it for an NPT barb, then screw a brass NPT barb in its place.

You are close enough that I can drive down in the service truck if necessary.

Bill Robertson
#5939

2628
03-10-2014, 04:43 PM
Is it leaking from the return line barb? (That's what the 3/4" barb is. Community commonly gets water flow backwards: Y pipe is outbound distribution, not return). If it is, easiest thing to do would be to pull out the pressed in barb, tap it for an NPT barb, then screw a brass NPT barb in its place.

You are close enough that I can drive down in the service truck if necessary.

Bill Robertson
#5939

Yes it's the barb that had the small heater hose coming off it,
Going into the pipe you suggested i get rid of. (Which i did!)
You give me a part number on the barb. And what size tap i need?
And i can get her done.
Also, How do i get the pressed in Barb out?
Feel free to drive down if you are bored though Bill?

Thanks once again!

Greasy DeLorean Mechanic
03-10-2014, 07:05 PM
To remove a pressed in barb you squeeze it in a vise, then twist whatever it is pressed into back & forth as you pull.

Your barb is so far gone that it may disintegrate when you try to squish it in the vise, in which case you'll need to cut it off flush with the back, then use the tap to do double duty: remove what's left of the barb at the same time it's cutting new threads.

1/2 NPT is ~7/8" actual OD. Use a 5/8" hose barb and you won't need to adapt the hose before running under the car. McMaster Part #5346K66.

I *HATE* working on K-Jetted engines. Even the simplest tasks take 10 times longer than they reasonably should. If I come down there I may bring a carb conversion with me.

When I changed my water pump it took me an hour or so, even without Chinese food.

Bill Robertson
#5939

2628
03-10-2014, 07:25 PM
To remove a pressed in barb you squeeze it in a vise, then twist whatever it is pressed into back & forth as you pull.

Your barb is so far gone that it may disintegrate when you try to squish it in the vise, in which case you'll need to cut it off flush with the back, then use the tap to do double duty: remove what's left of the barb at the same time it's cutting new threads.

1/2 NPT is ~7/8" actual OD. Use a 5/8" hose barb and you won't need to adapt the hose before running under the car. McMaster Part #5346K66.

I *HATE* working on K-Jetted engines. Even the simplest tasks take 10 times longer than they reasonably should. If I come down there I may bring a carb conversion with me.

When I changed my water pump it took me an hour or so, even without Chinese food.

Bill Robertson
#5939

Thank you Bill !
You are the man.
When i do the carb conversion, I'm getting you here to help me!

Greasy DeLorean Mechanic
03-10-2014, 07:33 PM
Have you seen this video yet? This is the procedure I use to remove my intake manifold:


http://www.youtube.com/watch?v=6lxsemJO-Gg

Bill Robertson
#5939

2628
03-10-2014, 07:40 PM
Yes i saw it! I'm Jealous! Very Jealous!
BTW Can you give me the part number for the studs on the water pump?
Getting rid of the bolts this time!

Boo
03-10-2014, 08:00 PM
No offensive to Bill, but you most probably don't need him there to do the carb conversion. Bill offered to come help me with mine, but I did it myself. When Bill DID come to my house, he helped me with the electrical ground bus. (Which I have yet to finish BTW, I still have to do the front radiator bracket connections.) Summertime, summertime. Bill makes a complete kit so the carb conversion is easy peasy! Just get an email from him with the step by step and you are good to go. Bill swore that at least one of my kjet hold down bolts would snap off in the block, but nope a little tapping on the wrench with a hammer and they all came out clean and easy. I think maybe the kjet was removed once before I got the car. The car had pjgrady stickers all over it. I removed them but the rear bumper one actually left raised lettering visible. That's where I put my oval IRE sticker. But if you look close you can still see pj Grady raised lettering under it. I guess I could have sandpapered it smooth before painting it with the SEM trim black, but I didn't.
But as far as the carb conversion, its just changing the fuel pump, running a rubber fuel line hose from front to rear, installing the fuel filter (I went with Bill's charcoal canister fuel filter bracket) and adjusting the throttle cable length. And of course bolting on the carb manifold. Like I said in another post, now I can remove and replace my carb manifold in a little over four minutes. No need to though, I can get at the distributor easily with the manifold on and I can even get a vacuum hose into the valley of death to clean it out with my manifold on. I still need to replace the rusty metal pipe in the valley of death with a rubber hose, but I just may wait till it starts leaking first. Summer is when most things happen on my D, I have off and I have to work in my driveway.
Oh I'm thinking of changing my license plate SUMMROFF from the Delorean to the Fiero and putting GIGAWHAT? on the Delorean. The only thing is that with the rear tag plate cover, I don't know if there's enough room to put a question mark sticker after GIGAWHAT.

2628
03-10-2014, 08:19 PM
The carb does sound easy. Thank you for the info!

Oh yea Bill. About the barb?
Are you saying that i won't need a tap once i get the old spout out?
That the new brass barb will thread itself in???
Thanks again!

Greasy DeLorean Mechanic
03-10-2014, 08:51 PM
No, you definitely need to cut threads. If you can't pull the steel barb out you'll need to let the tap cut it out as it's making the threads (steel barb is 3/4" OD, 1/2 NPT is nearly 7/8" OD -- the tap will cut wider than the barb).

Bill Robertson
#5939

2628
03-11-2014, 04:10 AM
So i need a 7/8 Tap?
Also can you give me a part number on the studs for the water pump?
Does McMaster have those also?

Thanks Bill !

Greasy DeLorean Mechanic
03-11-2014, 08:55 AM
No, you want a 1/2 NPT tap (.84" actual OD). TPI is the same as 7/8 UNF, but 7/8 UNF is a straight thread, not tapered (won't seal itself).

Bill Robertson
#5939

2628
03-11-2014, 06:13 PM
Bill, can you tell me which Tap i need from this list?
http://www.mcmaster.com/#npt-taps/=r1wpz9

Greasy DeLorean Mechanic
03-11-2014, 07:19 PM
Only a mad man is going to spend $50 on a pipe tap. Buy this one instead: http://www.ebay.com/itm/1-2-1-4NPT-TPR-GTD-HS-E5-Pipe-Taps-16222-5320-/310888567172?pt=LH_DefaultDomain_0&hash=item4862671184

Do you have a tap wrench that big? If you have a split wrench you should be able to put longer bolts in it to increase its capacity.

Word up: buy Made in USA taps whenever possible. Made in Germany taps are good too. Made in China taps are crap. Assuming they don't snap off in the hole, they leave ugly threads behind.

Bill Robertson
#5939

2628
03-11-2014, 07:29 PM
Only a mad man is going to spend $50 on a pipe tap.

Bill Robertson
#5939

What i was thinking!
Thanks!
How about the water pump mounting studs to replace the bolts?
McMaster Have them?

Greasy DeLorean Mechanic
03-11-2014, 07:32 PM
Yea. Can't remember the length. Let me run to Wally World real quick, then I'll measure a water pump after I get back. Thread is M8x1.25.

Bill Robertson
#5939

2628
03-11-2014, 07:34 PM
Thanks.

Greasy DeLorean Mechanic
03-11-2014, 08:59 PM
I estimate 50mm should do it:
- 22mm thick water pump mounting bosses
- 8mm tall nylocks
- 2mm thick washers
- 2mm exposed thread
- 16mm into block

Note that McMaster does not sell metric studs with shoulders -- only fully threaded. You need to stop yourself turning them in when they're deep enough. I Loc Tited mine to keep them in place.

If you're feeling particularly industrious you can cut the heads off some partially threaded bolts and tap them to become shouldered studs....

Bill Robertson
#5939