Vacuum Pump Failed- Dry?

[FratBoy]

I rebuilt my vacuum pump just 300 miles ago with sealed bearings.

I started to hear a noise so I popped it off. The bearings are gone and the pump is toast. Bearing races are still in the piston arm and on the roller axle

I haven’t dropped the oil pan yet to look for additional damage. Engine was still running when I parked it…

I’m trying to figure out how this happened. The pump was clean and dry inside. Is it supposed to be lubricated with oil pressure?

[ykobayashi]

Wow.

Everytime I’ve had my pumps open they were a little oily. I think they are splashed by the motor oil. Not dry.

Sounds like your bearing cages fell apart…for whatever reason.

I rebuilt two pumps this year. The original bearings had nylon cages. Un shielded. For forty year old bearings they looked great.

On my rebuild I used SKF rubber sealed bearings and I pried off the seals. I surmised that the originals were open so the replacements should be open. I didn’t buy the conventional wisdom (here) that the shields hold the bearings in. It just didn’t make any sense so I removed them.

Why kind of bearings did you choose?

[FratBoy]

I should clarify- pump was clean and dry inside Upon removal. And installation, for that matter.

Bearings came from Amazon: uxcell 626ZZ Deep Groove Ball Bearing Double Shield 626-2Z 80026, 6mm x 19mm x 6mm Chrome Steel Bearings. This at the recommendation of a rebuild thread author.

I’m trying to post pics but file size is too large. I’ll get that later when I’m on a desktop.

[ykobayashi]

What?!?

Where did you see that? Uxcell is bottom of the bucket Chinese quality. What did you pay $1 a bearing? We generally recommend SKF, NSK, Timken and others here. Typical cost is $15-$30 per bearing.

2Z bearings are shielded not sealed by the way.

Okay, that aside your housing shouldn’t be bone dry inside. Mine were oily like they were splashed but not dripping with oil like they had an oil jet. I think they get oiled by oil carried up on the chain, timer device and in blow-by.

My guess is that you had sufficient oil before and after but you used the cheapest bearings available. Their cages may have failed due to excessive engine heat or vibration.

[FratBoy]

I’ll add that I’m not likely to go back with sealed bearings. The seals didn’t keep the balls in and became additional fodder for damaging everything else.

[FratBoy]

I take it back. Sorry. I just double checked. The author of the thread I referenced used SKF. Perhaps this whole ordeal is due to a bad buy of cheap bearings.

I did wipe a film of oil off the inside. It was mostly dry though. I guess I was expecting lots of black sooty mess like I have seen in some threads.

I’m probably over thinking this.

[ykobayashi]

Yes, possibly. Chinese stuff is really hit and miss. Some of the stuff is great and others really suck. Uxcell is the brand I see in eBay for screws, hardware and electronics components when I do a sort for cheapest items first.

Here is the post where I photographed some of the pump rebuild. The original bearings were SKF six ball. The replacements were SKF 8 ball. Other differences like origin are discussed in the post. I liked the replacements a little better because they had metal cages as opposed to plastic. However the original bearings with the nylon cages seemed very durable after 40 years.

I just looked and you can get similar SKF rubber shielded 626 bearings for $8 on eBay. Not quite $15 as I’d said above. More like $15 for the set of two. I got a four pack for $18 which was great because I needed to rebuild two cars. Hopefully they won’t disintegrate like yours.

Preemptive defusing

[FratBoy]

I read your thread. Very good thoughts in there. I think I’ll rebuild with the same, open bearings. After I find a core pump for parts. And check the oil pan for metal and chain for wear.

I’ll also look at the front of the block for oil from the area. If it’s there, it was in the pump.

[ykobayashi]

Good luck. Count up all the balls you find down there. You can tear apart the uxcell bearings to see how many are in each one. Hopefully you can find all of them. If you lucked out they all fell down the timing gallery and ended up in the pan.

[FratBoy]

Here's the damage I have seen so far. I didn't have time to investigate much further. I'll get back to it in the next few days.

These are not great pics, but you can see where bearing bits are missing and where the cam has worn the mechanism.

Thank you, ykobayashi for your sharing your experience and your quick responses.

Pumps are proving hard to find in the usual places. I have a dual diaphragm pump core from a '79 300SD in my collection, but it ain't gonna help here much.

[vstech]

The oil pump is chain drive, make sure that chain is intact. I’d hate to think you have been operating without oil pressure in the car.

[ykobayashi]

That pump is in bad shape. You can still find old ones in the JY. I’d get some new bearings in that thing. Then start hunting the JY for a replacement pump.

[FratBoy]

I found the answer to my original question. FSM 07.1-240.

Vacuum pump is lubricated through the injection timing device.

I am going to remove some parts of this vacuum pump, run the engine for a bit and remove the pump to confirm oil is coming through the timing device.

[Diesel911]

Originally Posted by FratBoy

I rebuilt my vacuum pump just 300 miles ago with sealed bearings.

I started to hear a noise so I popped it off. The bearings are gone and the pump is toast. Bearing races are still in the piston arm and on the roller axle

I haven’t dropped the oil pan yet to look for additional damage. Engine was still running when I parked it…

I’m trying to figure out how this happened. The pump was clean and dry inside. Is it supposed to be lubricated with oil pressure?

For anyone reading it need year and model of the vehicle.

You are not saying why you rebuilt the vacuum pump to begin with. There is a bushing behind the timer gear if that wear is stressing the vacuum pump and ruins even a new vacuum pump.
You check that by using a dial indicator and pushing the timer gear to the read and pulling it forward and looking at the end play.

"with sealed bearings"; The bearings need to be open for engine oil to lube them. Another issue is that if the bearing cage inside of the bearings is plastic the plastic falls apart. So, you need open bearings with steel bearing cages.

[Diesel911]

Originally Posted by FratBoy

I found the answer to my original question. FSM 07.1-240.

Vacuum pump is lubricated through the injection timing device.

I am going to remove some parts of this vacuum pump, run the engine for a bit and remove the pump to confirm oil is coming through the timing device.

Note that there is also another setup to do that that has a central bolt with no drilling through it. It depends on your engine and the related parts.

I am going to guess that the engines that used diaphragm vacuum pumps are the ones that did not have the drilled central bolt.

In any event the back side of the vacuum pump should not have been dry.