If I remember the threaded stud is around 4" long, it is not a piece of All thread but it is a Hex key stud.

What I did was I ask the guy for the longest stud with a full thread and he came up with 4" and I think it was a 3/8"

I have all of the bolts and studs somewhere in the garage and as soon as I can remember where I left them I will list the sizes on the article for you.

Jim

 

Looks very similar to when my power steering pump melted down, sent a very similar amount of junk into the gear case, I had just pulled the front cover off as well and replace the oil pump at everyone sugestion on here. The oil pump did show some sign the metal had gone through it when I removed it. Fortunatly from the oil pump the oil goes to the filter! Very nice write up!

 

Does anyone have the Cummins part number for the reseal kit? I have a slight oil leak coming from my bottom diaphram and want to have the o-ring on hand before I unbolt it. Please pm me the part number? Thank you

 

Do you have the 2 diaphragm type vacuum pumps or the vein type vacuum pump? Being that your sig only shows '92 model trucks/vehicles, you should have the vein type pump. However, you mention a diaphragm is why I'm asking.

The diaphragm vacuum pumps can't be resealed, only replaced at the cost of about $160 each. The vein type pumps can be resealed. The reseal kit for the vein type pumps is Cummins P/N 4089742.

 

jimbo I have a 90 motor in my RC.
So I cant reseal the one leaking diaphram

 

A little off topic but does anyone know how hard it is to convert to the intercooled style and if theres a thread with pictures? I searched but couldn't find anything. I'll donate my good pod to who ever wants it when I'm done.

 

Gotcha. I'd say, if the other pump is pulling a good vacuum, ditch the lower pump and make a block-off plate like I did. I've got a picture of it somewhere around here...



1/8" piece of aluminum, some ultra copper gasket maker, (3) 6mm x 1.00 screws, threadlocker and lock washers did the trick. Did that back in 2009 and still running it the way you see it above.

Just swap vacuum pumps from one to the other. Removing the vacuum and power steering pump assembly from the motor would make the job far easier to do.

 

I have a '91 too but it's intercooled so I've got the vane style PS pump. is the failure of the vane style pump just as catastrophic? geez, just the thought of not being able to stop my truck (or truck + BOAT ON TRAILER) and I almost soil myself...

 

According to the Dodge manual the bolt used to reassemble the gear to the power steering pump is a 3/8" 18 thread..... Does anyone know where to find this thread size since 3/8" only comes in 16 and 24 thread? A 5/16" bolt is the only size that's close that comes in an 18 thread. I'm trying to reassemble mine and I'm stuck with it apart, any help would be great!

 

Did you try a 3/8 fine thread bolt? don't think it was anything special,
I went to King Bolt and ask for the longest threaded stud he had, studs are hardened and fine thread, also got some Grade-8 washers and nuts to pull the gear onto the shaft with.

Ill see if I had any notes anywhere with my pictures.

Jim

 

Awesome, anything would help! There are two different thread sizes for 3/8", they are 16 and 24. I don't want to mess up the threads inside so if you can help I would greatly appreciate it. Thanks!

 

Ay--uh...
1. Typo's happen, as well as misreads.
2. It wouldn't be a strange thread. Maybe metric, but not strange.
3. You aren't going to mess up a thread by trying to turn the wrong bolt with finger pressure. If it's right it'll spin right in and not have excessive wobble after insertion.

So grab a fine thread bolt and try it.

 

The thread for the bolt that is required to reassemble it is 3/8 - 16 thread. Make sure you use a grade 8 or higher, anything less will strip pretty easy!

 

This is the hardware needed to both remove and reinstall the drive gear from the non intercooled vacuum pump.

The bolt is an M14-2.0X55mm
3/8"-16 X 4.0 inch stud,
3/8" grade 8 hex nut
flat washers grade 8
Large o-ring end of pump housing. # 128 1 1/2" OD X 1 11/16" ID

Smaller o-ring under vacuum chamber. #212 1 1/4" OD X 7/8" ID

 

Thanks for up dating the post. This is exactly the info I needed to go to the hardware store with.