What happens when your vacuum pump stops working.
08-20-2007, 06:41 AM
#1
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Thread Starter
What happens when your vacuum pump stops working.
Part-1
I was driving on the freeway and I pulled onto the off ramp to exit and as I was coming to the red traffic light ahead behind a line of already stopped cars I suddenly found I had no brakes but realized I only had no power assist as 4 tons of truck was slowing down from 70 miles per hour, I found myself having to use both feet to stand on the brake pedal to make the light.
Before this the brakes were working perfectly and this condition came on within an instant.
This gave me no warning, as it was about to fail.
I am just thankful my wife had not been driving the truck at this time.
This will cover the removal and the repair of the engine driven vacuum pump used on the early pre 91.5 engines.
It is identified by the 2 round diaphragm chambers one facing downward and the other facing the driver’s fender.
After removing and plugging the power steering lines, disconnect the vacuum hoses and remove the 2 metric bolts that secure the assembly to the timing case.
Here you can see the fragments that remain of the bearing cage and the remaining ball bearings in the gear housing. Luckily all of the fragments remained in the case or made their way into the oil pan and did not get picked up by the gears which could have been as devastating as the “KDP” dowel pin coming loose.
Withdraw the assembly as an entire unit and move it to a suitable workplace.
The drive gear is a press fit and will need to be removed by pressing it off from the shaft.
You can do this without a commercially made puller.
To do this you will need to get a threaded bolt, it needs to be a hardened (Grade-8)
And you will need to get a small stud to place behind the bolt to reach the power steering pump shaft. I bought 2 studs of different lengths, they are carburetor studs and the thread pitch is unimportant as the are only using them to push against.
So what you will do is stand the pump on end and drop the stud into the hole so it sits in the hole on the end of the pump shaft. Then thread in the Grade-8 bolt you are going to be using to push the pump gear off with.
Using an impact wrench, hold onto the gear with a GLOVED hand and carefully drive the pump gear up and off the end of the pump shaft.
As you do so the gear will raise and the entire eccentric bearing will come off with the gear.
As you drive the gear off the shaft you will see the bearing or in my case the remains of the ball bearing and all of the small fragments behind the gear.
The bearing is pressed into an eccentric machined into the back of the drive gear so as this gear rotates the eccentric applies the in and out motion that is transmitted through the pushrods to the back of the diaphragms creating vacuum.
When the ***** fall out then the bearing is unable to walk the pushrods up and down so there is no more vacuum AND there is no more power brakes, AC controls, cruise control.
Here you can see the damage the hardened parts did to the aluminum housing. One of the pushrods fell completely inside the case also look at the backside of the hardened gear, the bearing fragments galled that up as well.
All of this damage happened probably within a few minuets.
This was all that was left of the ball bearing on the back of the gear.
You can now remove the 4 nuts and remove the power steering pump from the back of the housing.
This was some of the damage to the backside of the housing where the back of the gear caught the hardened fragments as they tried to enter the gear case.
I used my Dremel and removed the damaged metal from the housing and polished I up.
I was driving on the freeway and I pulled onto the off ramp to exit and as I was coming to the red traffic light ahead behind a line of already stopped cars I suddenly found I had no brakes but realized I only had no power assist as 4 tons of truck was slowing down from 70 miles per hour, I found myself having to use both feet to stand on the brake pedal to make the light.
Before this the brakes were working perfectly and this condition came on within an instant.
This gave me no warning, as it was about to fail.
I am just thankful my wife had not been driving the truck at this time.
This will cover the removal and the repair of the engine driven vacuum pump used on the early pre 91.5 engines.
It is identified by the 2 round diaphragm chambers one facing downward and the other facing the driver’s fender.
After removing and plugging the power steering lines, disconnect the vacuum hoses and remove the 2 metric bolts that secure the assembly to the timing case.
Here you can see the fragments that remain of the bearing cage and the remaining ball bearings in the gear housing. Luckily all of the fragments remained in the case or made their way into the oil pan and did not get picked up by the gears which could have been as devastating as the “KDP” dowel pin coming loose.
Withdraw the assembly as an entire unit and move it to a suitable workplace.
The drive gear is a press fit and will need to be removed by pressing it off from the shaft.
You can do this without a commercially made puller.
To do this you will need to get a threaded bolt, it needs to be a hardened (Grade-8)
And you will need to get a small stud to place behind the bolt to reach the power steering pump shaft. I bought 2 studs of different lengths, they are carburetor studs and the thread pitch is unimportant as the are only using them to push against.
So what you will do is stand the pump on end and drop the stud into the hole so it sits in the hole on the end of the pump shaft. Then thread in the Grade-8 bolt you are going to be using to push the pump gear off with.
Using an impact wrench, hold onto the gear with a GLOVED hand and carefully drive the pump gear up and off the end of the pump shaft.
As you do so the gear will raise and the entire eccentric bearing will come off with the gear.
As you drive the gear off the shaft you will see the bearing or in my case the remains of the ball bearing and all of the small fragments behind the gear.
The bearing is pressed into an eccentric machined into the back of the drive gear so as this gear rotates the eccentric applies the in and out motion that is transmitted through the pushrods to the back of the diaphragms creating vacuum.
When the ***** fall out then the bearing is unable to walk the pushrods up and down so there is no more vacuum AND there is no more power brakes, AC controls, cruise control.
Here you can see the damage the hardened parts did to the aluminum housing. One of the pushrods fell completely inside the case also look at the backside of the hardened gear, the bearing fragments galled that up as well.
All of this damage happened probably within a few minuets.
This was all that was left of the ball bearing on the back of the gear.
You can now remove the 4 nuts and remove the power steering pump from the back of the housing.
This was some of the damage to the backside of the housing where the back of the gear caught the hardened fragments as they tried to enter the gear case.
I used my Dremel and removed the damaged metal from the housing and polished I up.
08-20-2007, 06:43 AM
#2
Administrator
Thread Starter
Part-2
I cleaned all of the parts using solvent and dried them using compressed air.
I took what was left of my bearing to my local bearing and drive shop and they matched up my pieces with a nice new ball bearing with all of the *****.
If you look in the background you will see the 2 carburetor studs I used to push off the pump shaft. Compare them to the pump pushrods to get an idea for the length.
The ***** stuck to the magnet were all that were left, a few made their way into the pan.
Each missing ball were a bomb waiting to go off and they decided weather or not to kiss the timing gear on their way past it.
You can remove the old bearing yourself if it is in pieces by supporting the bearing on it’s side and striking the race with a chisel 180* apart then it should come off but the best and safest way would be to take it to your good auto parts/ machine shop and they can press it off easily and should charge you only a few dollars for the job.
They can also press the new bearing back onto the eccentric on the back of the gear.
If you do it remember to line up the bearing carefully and press it on, when you get towards the end, use the old bearing race on top of the new bearing so you do not put pressure on the outer race or bearing cage which would destroy the bearing.
Most of all be careful and go slow, remember that if you damage this gear you can bet you are going to pay dearly for it from your dodge dealer if they are still available.
So if you do not feel comfortable with it, best take it to a machine shop.
Here are all of the parts you should have ready for reassembly.
Now to reassemble the pump you will need to get yourself a long hardened threaded stud, (I am thinking it was a 3/8 fine thread) I am sorry but I do not remember the size but when I find it I will add it to these instructions.
You can see this in the background.
You will also need a large thick flat washer.
If you look in the housing where the end of the power steering pump fits through you will see an o-ring, this is what keeps the engine oil from leaking out of the housing and down the front of the pump.
By all means replace this $0.30 part now before you forget, you can get this the same place you got the bearing.
Once you replaced the o-ring, lubricate it and reinstall the pump into the housing and replace the 4 nuts.
Now set it up on end and apply a film of oil to the inside of the housing where the bearing race will set and also on the pump shaft.
Next thread the stud into the end of the pump shaft and then set the gear over the stud and center it on the shaft.
Put some oil on the threads of the stud and put the large washer on, next screw on the nut. Snug them down so it holds the gear in place.
Using the impact wrench very carefully and slowly draw the gear down into the housing taking care it is going into the housing strait, this is VERY IMPORTANT.
Draw it up until it stops.
You are all finished.
After you reassemble the rest of the pump then replaced the vacuum diaphragms making sure you first lubricate the pushrods before you insert them into the holes.
Then install the diaphragms and reinstall the crossover hose.
I used a fiber optic scope to look inside the housing to make sure everything was ok. You can skip this part.
Now take it back to your truck and assuming you cleaned up any mess in the gear case, install a new gasket and then replace the pump.
You are all finished.
What you will need to get:
Housing gasket.
O-ring for back of housing.
Ball Bearing (old one had NAT 108 stamped on it)
Big grade-8 bolt to push off gear.
Assorted carburetor studs.
Long hardened threaded stud and nut.
Large flat washer to pull on gear.
A couple hours of your time.
When I get a chance to get the sizes I will come back and add them.
I hope I helped you to save yourself a few dollars and to get your power brakes back.
Take care my friends.
Jim
I cleaned all of the parts using solvent and dried them using compressed air.
I took what was left of my bearing to my local bearing and drive shop and they matched up my pieces with a nice new ball bearing with all of the *****.
If you look in the background you will see the 2 carburetor studs I used to push off the pump shaft. Compare them to the pump pushrods to get an idea for the length.
The ***** stuck to the magnet were all that were left, a few made their way into the pan.
Each missing ball were a bomb waiting to go off and they decided weather or not to kiss the timing gear on their way past it.
You can remove the old bearing yourself if it is in pieces by supporting the bearing on it’s side and striking the race with a chisel 180* apart then it should come off but the best and safest way would be to take it to your good auto parts/ machine shop and they can press it off easily and should charge you only a few dollars for the job.
They can also press the new bearing back onto the eccentric on the back of the gear.
If you do it remember to line up the bearing carefully and press it on, when you get towards the end, use the old bearing race on top of the new bearing so you do not put pressure on the outer race or bearing cage which would destroy the bearing.
Most of all be careful and go slow, remember that if you damage this gear you can bet you are going to pay dearly for it from your dodge dealer if they are still available.
So if you do not feel comfortable with it, best take it to a machine shop.
Here are all of the parts you should have ready for reassembly.
Now to reassemble the pump you will need to get yourself a long hardened threaded stud, (I am thinking it was a 3/8 fine thread) I am sorry but I do not remember the size but when I find it I will add it to these instructions.
You can see this in the background.
You will also need a large thick flat washer.
If you look in the housing where the end of the power steering pump fits through you will see an o-ring, this is what keeps the engine oil from leaking out of the housing and down the front of the pump.
By all means replace this $0.30 part now before you forget, you can get this the same place you got the bearing.
Once you replaced the o-ring, lubricate it and reinstall the pump into the housing and replace the 4 nuts.
Now set it up on end and apply a film of oil to the inside of the housing where the bearing race will set and also on the pump shaft.
Next thread the stud into the end of the pump shaft and then set the gear over the stud and center it on the shaft.
Put some oil on the threads of the stud and put the large washer on, next screw on the nut. Snug them down so it holds the gear in place.
Using the impact wrench very carefully and slowly draw the gear down into the housing taking care it is going into the housing strait, this is VERY IMPORTANT.
Draw it up until it stops.
You are all finished.
After you reassemble the rest of the pump then replaced the vacuum diaphragms making sure you first lubricate the pushrods before you insert them into the holes.
Then install the diaphragms and reinstall the crossover hose.
I used a fiber optic scope to look inside the housing to make sure everything was ok. You can skip this part.
Now take it back to your truck and assuming you cleaned up any mess in the gear case, install a new gasket and then replace the pump.
You are all finished.
What you will need to get:
Housing gasket.
O-ring for back of housing.
Ball Bearing (old one had NAT 108 stamped on it)
Big grade-8 bolt to push off gear.
Assorted carburetor studs.
Long hardened threaded stud and nut.
Large flat washer to pull on gear.
A couple hours of your time.
When I get a chance to get the sizes I will come back and add them.
I hope I helped you to save yourself a few dollars and to get your power brakes back.
Take care my friends.
Jim
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Diesel_Dawg (05-01-2018)
It's in the sticky.
08-20-2007, 03:36 PM
#5
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Jim I hope you have not forgotten the three smaller o-rings! There is one between the bottom vacuum pump bracket and the drive support and there are two where the vacuum pump canisters attach. Cummins has a vacuum pump seal kit with all these in it, reasonable too. I do not have the number for the kit but I could post the Cummins p/n's for the o-rings and gasket.
08-20-2007, 03:36 PM
#6
Registered User
Thank You for this great info.
One thing I don't get, I found the power steering pump for this engines at rock auto and they sale from $50-$150 their rebuild units. Is this right? I thought someone said the ps pump and vac pump cost about $500. It was My understanding that all 1st gen use the same gear driven pump combination, right?
Thank You.
One thing I don't get, I found the power steering pump for this engines at rock auto and they sale from $50-$150 their rebuild units. Is this right? I thought someone said the ps pump and vac pump cost about $500. It was My understanding that all 1st gen use the same gear driven pump combination, right?
Thank You.
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08-20-2007, 03:46 PM
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The earliest 1st Gens used this twin canister type vacuum pump. The canisters are available remanufacured, Cardone p/n 64-1300 Approx. $140. Cummins will want your 1st born for them...
Some Cummins parts are very reasonable but not these canisters, they are over $300 bucks each last I checked.
Some Cummins parts are very reasonable but not these canisters, they are over $300 bucks each last I checked.
08-20-2007, 06:13 PM
#10
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Thread Starter
It is a good idea to split the vacuum line where it branches off between the 2 diaphragms and install a check valve in-between each one.
This way in the event that one chamber fails then you will not loose the ability to supply vacuum, although each unit has a simple check valve used in its basic operation, it is sometimes the part that fails.
I like redundancy especially in my braking system.
Jim
This way in the event that one chamber fails then you will not loose the ability to supply vacuum, although each unit has a simple check valve used in its basic operation, it is sometimes the part that fails.
I like redundancy especially in my braking system.
Jim
08-20-2007, 06:36 PM
#12
Registered User
The vacuum chambers/pots will interchange with the ones on the Ford diesels, as their bolt patterns are identicle.
Also, the chambers are a direct swap for nearly all, if not all, belt-driven vacuum-over-hydraulic brake pump kits.
The ones on the Dodge/Cummins application utilize a hose from pump top to bottom and most of the others do not have this feature; but, they will swap and will work.
Does anyone know the purpose of that rubber hose ??
08-20-2007, 08:07 PM
#14
Registered User
What length is this stud? It's important, since it has to be threaded from one end to the other.
08-21-2007, 05:40 AM
#15
Administrator
Thread Starter
I had a bunch of fuel check valves for Detroit Diesels I have used but you could get a set of them from your welding supply, get a set of Reverse Flow Check Valves that are used for torches, they can set you up with the left hand gas fittings to hose barb connections.
Get the largest size you can find, like 3/8"
Jim
Get the largest size you can find, like 3/8"
Jim