Nice Job.. i just did mine last week and doing another one that i bought from Ebay....
This is nice...I vote sticky too! Beautiful dog...already oil-colored and ready for the FCar workout.
Hey Guys,, I'm in the process of doing my belts and noticed a droplet of water on the pump. I took it apart to confirm my suspicions. Everything looks ok still, but the spindle sleeve that the seal sits on is too gone. I'm struggling to find what the pump part number is, and what spindle I need to buy. Based on the bearing size, do I have the large bearing pump 121253? And is the spindle pn 121253? Looks like a spindle will cost me $200, plus the bearings and the seal. Is it still worth rebuilding, or do I have better options?
If the housing is not badly corroded these pumps are always worth rebuilding. And after the rebuild much better than ANY of the junk, which is currently available from the official parts dealers. Every mechanic with a lathe is able to restore the seal seat. I do it each time I rebuild these waterpumps. With the needed skills and care such a restored shaft is better than most of the new ones available. I have seen some with almost half a mm radial runout tolerance between bearings and seal seat, what means they are plain junk. The older pumps with the two-piece seal I convert to the latest version with the one-piece seal. If costs are not an issue, one option I would recommend is this: https://www.nicksforzaferrari.net/nff-performance-water-pumps.html Best from Germany Martin
My last rebuild was done by Flying Dutchman slightly over 2 years ago. No leaks. I keep drive belts only tight enough so there is no squealing when cold engine is first started. The belts will tighten due to engine block expanding when it warms. No sense putting excessive loads on bearings.
Thanks for the info. Any idea what diameter I can go down to without affecting the seal effectiveness?
Sorry for not being clear enough. You have to restore the seal seat to its original diameter. Brief procedure as follows: Cut away approx. 2mm (diameter). Make a sleeve with a press fit inner diameter for the turned down shaft and an outer diameter some half a mm larger than the the finished dimension. Press the sleeve onto the shaft. I make the sleeve from stainless steel. For peace of mind I add a slight smear of Loctite 648. Take it onto the lathe again and adjust radial runout tolerance of the bearing seat (where you clamp the shaft) to the best possible result. You should achieve 0.02mm. Less is better. Turn down the seal seat to its original dimension. Here's a related thread I created 8 years ago. It covers the conversion and lacks the step with restoring an old shaft, but the principle is the same. The advantage of converting an old shaft to the new style is, that you have to turn down the seal seat anyway, no matter how it's still looking. (19mm old/16m new). https://www.ferrarichat.com/forum/threads/308-w-pump-altering-design-old-to-new.328021/ For a certain period I offered it as a service for the European FChatters and shared the market with a buddy from the Seattle area, who served the US-market. I made a few, but unfortunately my labour seemed to be too expensive and folks preferred to purchase the common Chinese or Indian junk. Best from Germany Martin
Martin, would it worth having some 151253 shafts made along with a sleeve to adapt the housing to the one-piece seal? It should be cheaper than the aftermarket pumps and cheaper than the time/labour to modify the original parts. Can't be more than $20 for both parts.
I cannot remember, whether cutting work on the housing was mandatory for the original Ferrari one piece seal 152051. For my more modern one piece seal cutting was necessary to maintain precise working height according to the manufacturers directions. How many shafts would I have to order to get them for less than $20.00/each in decent precision? Best from Germany Martin
I could probably get 20 in stainless for that. Quality is usually good for small numbers as they are hoping for more business and I always say there is no rush so they fit them in when they have a gap in production. If they are not within spec you just get them to remake them.
If anyone is ordering shafts, let me know. I ended up a getting a crappy aftermarket one for now to get the car on the road
Friends, I have a couple questions about the water pump. What keeps the shaft in the correct position for the pulley and the impeller? Should you put the pulley on before you mount the pump or afterwards? If you tap the pulley on after the pump is mounted, can misaligned the shaft. I've always had mine rebuilt, and I'm just curious. Thanks, Rob
Friends, Where does the pulley rest against, the inner race of the bearing? I am confused on what keeps the shaft line correctly for the pulley to be perfectly aligned with the motor and the alternator? Rob
Hi Rob, maybe a 3D-CAD section screenshot helps more than thousand words. If you look at the assembly without the pulley -sorry I haven't modelled one yet- you see, that nothing is held together firmly as long as the pulley is not installed. The installed pulley rests against the inner race of the bearings with the spacer in between. NEVER try to install the pulley after the pump is on the engine. You have to support the shaft on the impeller side while installing the pulley. If the shaft is not supported you will try to push it out towards the engine side and possibly damage the bearings or -even worse- destroy the seal. (This CAD-drawing shows a modern 1-piece seal.) Image Unavailable, Please Login Image Unavailable, Please Login Best from Germany Martin
Friends, On my US car with the two belt pulley there was this washer that was underneath the pulley, that obviously rested against the inner race of the outer bearing and the indentation of the 2 belt pullet. Has any of you ever seen this before, it's not in the parts book? Here is a picture of the two pulleys from the 74 Euro and the 75 US GT4.... Both were updated with larger bearing pumps. I am sure my US car has the weird washer under the pulley as we speak, but the euro just rode on the shaft of the water pump solo. It looks like there is a pressed in metal piece that captures the woodruff key and presses that against the inner race of the outer bearing?? Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Martin, Thank you so much, the guy that has been rebuilding my water pumps for decades said it's best to put the pulley on while he adjusts the whole unit. That was news to me because I've replaced the one on my US car probably five times and always put the pulley on after the water pump was mounted and sealed and never had any problems. I'm not saying that's right I'm just saying what I did. The pulley is heavy and always in the way when I am working on that side of the engine so that is why I always did that. I just lightly tapped the pulley on until the threads appeared then tightened in down using a old belt I don't see the c clip in your drawing? I have another question. He was going to rebuild an extra water pump I had for my car that's running right now. Can I put the pulley on before I mount it, or does it need to be on while he's rebuilding it? This is why I'm confused. I read 10 different write ups on how to rebuild the water pump, but none mentioned having the pulley on there, and I am trying to get my head around that. How come Rui never said anything about that in the original post? So how do you mount the pulley correctly? Like if you bought a NOS one? Thanks for you advice Rob
Yes, the C-Clip AND the flat spring washer- are still missing on my CAD model of the housing. They are in front of the inner bearing. (good occasion to add the parts not Regarding installing the pulley without supporting the shaft on the impeller side you can have luck and the pulley goes onto the shaft quite easily or you can have less luck and the tolerances are that way, that the pulley needs some force to go onto the shaft. Then chances are big, that you damage the bearings or even the seal. I had both variants on the pumps I have rebuilt until today. Notice, that there are certain tolerances there. So I ALWAYS support the shaft on the impeller side when installing the pulley. Regarding your second question. You simply cannot rebuild the pump with the pulley on the shaft. Or have I misunderstood something? Best from Germany Martin
Martin, I guess what I was trying to say is how do you support the impeller side of the shaft. Let’s say you bought a new water pump from Ferrari and you want to add the pulley on to it. How would you do that without damaging the bearings in the seals? Would you put the acorn nut in a vice and then tap the pulley on the shaft or maybe put the shaft into the pulley on a hard surface and tap on the acorn nut to get it installed? Rob
Rob, both ways would be correct. It's simply important, that one end of the shaft is supported and the force needed to install the pulley has no chance to go across the rolling elements ( balls ) or has no chance to push out the shaft towards the impeller direction. I even sometimes use my lathe to install the pulley. I put the acorn nut into the chuck and push the pulley with the help of the tailstock. Here's the CAD with the circlip and spring washer added: Image Unavailable, Please Login Image Unavailable, Please Login Best Martin
Friends, Has anyone seen a washer of this type placed between the two belt pulley and a large bearing pump? It was probably placed on there by one of the Ferrari techs that worked on the car before I got it. I know that the large bearing pulp never fit the stock original two belt pulley so the pump had to be modified a bit, and I even had a friend put the pulley on a lathe and turn down a little bit of the inside so that the pulley would not rub on the fins of the larger bearing pump. Rob
Rob, I have not done one of those in many years but when I owned my 308 I just rebuilt my own pumps seals and all. You can put the pulley on before or after install. There is not pressure on the shaft or bearing. As you noted at most a light tap send the pulley home over the woodruff key. Then minimal torque is needed with just a wrench and strap wrench holding the pulley to tighten the pulley nut. You want the pulleys parallel so I would install after the pump is installed. This way you can see if you need a shim or what size shim is needed. There is some tolerance there in pulley parallelism. Using your eye and straight edge gets the job done. Finally, you should sell me the crappier of your two GT4's so I can make a vintage racecar and go race with Pen. LOL....Stop hording all the GT4's!
