Originally Posted by BLKTOPTRVL
(Post 12202890)
OK, BUYAUTOPARTS lists a Mazda RX7 PS Pump as A1-Cardone Part number 21-5814. This is WRONG. That part is for a 90-95 Mazda MPV.
It has a splined shaft. I called Cardone and the proper part number is 21-5846. This is not available anywhere in the country as far as I can tell. The attached pic shows the wrong part (splined shaft) and the Mazda RX7 Pulley (Keyed.) I searched for and found the MPV pulley - it is serpentine and therefore of no use. |
Is the diameter the right size? If it is, it might work anyways. If the fit is good on the diameter, the grooves won't really matter.
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Originally Posted by TonyD89
(Post 12202899)
Is the diameter the right size? If it is, it might work anyways. If the fit is good on the diameter, the grooves won't really matter.
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Ahhh, no key way, my bad.
I edited to say a keyway is most likely cheaper than splines. Splines are very expensive.. |
Agreed. Which is why I find it interesting that newer pumps are splined when the don't really need to be. A key would do just as well.
Anyway. I just spoke to a sales engineer at a gear company. (I was looking for a inside geared collar that could go over the splined shaft, and fit inside the pulley hub. The salesman suggest that instead, I just look for an oilite (soft bronze) collar that will fit inside the pulley and can be pressed over the splines. The splines would cut into the bronze and make a locked fit. Unfortunately, it might take a couple tries to find the right thickness bushing and in the meantime the shaft might be damaged. But it is still anther option of all others fail. |
The problem with pressing that bushing on like that is the difficulty in getting the pulley to run truly perpendicular with the shaft. Might get a case of the wobbles, then your bearing and seals get worn out too quickly. Plus then you would still have to have a keyway cut through the brass and the steel shaft. Might cost you more than it's worth
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Just had a thought. After replacing any o-rings and such, you could lap the mating surfaces of your old pump housing and then potentially seal it with a type-2 sealer or equivalent anaerobic. Then you wouldn't necessarily need the gasket set. Don't know if that helps
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Originally Posted by professionalpyroman
(Post 12203111)
Just had a thought. After replacing any o-rings and such, you could lap the mating surfaces of your old pump housing and then potentially seal it with a type-2 sealer or equivalent anaerobic. Then you wouldn't necessarily need the gasket set. Don't know if that helps
My goal right now if I have to machine is to make no changes to the pump at all, but to the pulley hub. I am currently taking a mold of the space between the shaft and the pulley to take to a local machine shop to see what can or can't be done on a press. It's funny, other than the fact that I am not able to drive my car, I am enjoying this research and fab project. You know if lead (or something not toxic dried/cooled to something that could provide just enough grip on the splined shaft without being deformed by the heat/torque, it would be easy to loosely mate the hub to the shaft - and then pour in that filer material. |
If the pulley hole is larger than the shaft diameter, have bushing machined that you can cut a keyway in. No need for a pour or lead. Measure shaft, measure hole, you're done (let the machinist do this, he will be able to precision measure the stuff).
Also, look close at this key. If it's a Woodruff key, there doesn't need to be a full length slot (if there is one now). This key could be used instead of a standard straight key if that is what's in there now. A machinist will know where you're going with this if you talk to him. A Woodruff key won't cut your newly machined bushing in half. I'd try to make the keyseat deep enough to hit the old keymay, locking it all together. A good machinist should not have a problem getting the whole shebang done right. Might cost a bit though unless you know someone. I think they might have gone to the splines because of the weight of the vehicle it was put in. Even if they didn't up the pressure of the pump, I bet the heavy MPV puts a greater load on the pump to just turn the wheels as compared to the light front end of the RX7. In fact, after thinking more on it, the only thing different might be the pressure relief valve. That might be something to think about. |
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OK, I have received my rebuild kit, so I am going to document the process.
I have a few concerns, for those of you who know vane pumps... I guess I will find out if I did OK tomorrow when I run it.
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Congrats and I am hoping for complete success. I don't think you hurt anything at 200 degrees. I guess I misunderstood your problem when I made my last post.
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Originally Posted by TonyD89
(Post 12203713)
Congrats and I am hoping for complete success. I don't think you hurt anything at 200 degrees. I guess I misunderstood your problem when I made my last post.
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*#%y(*&y#$* i can't believe this...
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WTF...
I get the pump together, put all the accessories back on. Install it back into the car... And then when putting the Power Solenoid back onto the pump I snapped the threaded head off the solenoid! I can't believe this crap! I thought I was being careful, but the solenoid takes a 17mm wrench and what seemed to be the slightest tightening and it's gone! Now I have to try to find a solenoid. Apparently these threads are not part of the body, but brazed on?I may try some of that Devcon Weldit. EDIT: Looks like I am not missing anything with the Solenoid not attached... I put it on my bench tester and unless it is not the simple positive/negative voltage it appears to be (two wires) is does not do anything any way. Tomorrow I will buy a bolt to put in it's place and see how the car drives. |
hey bud,
you may want to look at the FSM on that solenoid. Its a control item. Check out the section on fuel and emissions for your car. It got lumped in with all the sensors at the end of that section. Probably want to take a look. You can probably see if one of these guys with a junked pump can send one to you for $20 or so... |
A M14x1.5 Oil Drain Plug Fits perfectly.
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The piece the threads broke off of looks like a cap of some sort. Do you think you can get it off? Maybe you could tap it M14 X 1.5, get a smallpiece of metric threaded rod from McMaster, drill a hole in it, cut it to proper length, and now you're done (maybe a little loctite on the solenoid side).
Be very careful (which I think you will be) messing with the "cap", do everything possible to see if there is a spring under it. I don't want you unscrewing it and then boing! Parts go flying (been there before). Yeah, seeing the o-ring that makes the seal, probably pretty low torque. |
Originally Posted by TonyD89
(Post 12204710)
The piece the threads broke off of looks like a cap of some sort. Do you think you can get it off? Maybe you could tap it M14 X 1.5, get a smallpiece of metric threaded rod from McMaster, drill a hole in it, cut it to proper length, and now you're done (maybe a little loctite on the solenoid side).
Be very careful (which I think you will be) messing with the "cap", do everything possible to see if there is a spring under it. I don't want you unscrewing it and then boing! Parts go flying (been there before). Yeah, seeing the o-ring that makes the seal, probably pretty low torque. The car drives just as it did before. I get the feeling that over the 30 years I have owned the car, the Speed Adjusting feature of the PS failed and I didn't notice. And as I said, that module does nothing now and is not really needed. For now, I will see how long this rebuilt pump lasts while I continue my search for another to rebuild (to have as a spare). I am not sure yet if I did a good job rebuilding - but it did survive it startup and a 25 mile trip today. It pumps and so far it doesn't leak. The only thing I don't like is that there seems to be a rubbing noise coming from the rubber seal under the new bearing (I didn't lube it when I put it in, I would have thought that the PS fluid would lubricate it... Guess I may have been wrong about that, but I am learning). I really feel that any maintenance I need to do in the future will require that I rebuild more parts myself; so this has been a good experience. |
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