Lets chat about vacuum pumps.... and exhaust brake stuff

[AH64ID]

Well it looks like the squeaky bearing in my accessory drivetrain is the vacuum pump.

What sucks is I had it replaced when the motor was rebuilt 35K miles ago. The pump I removed had 85K miles on it and worked like new....

Anyhow, I always told myself that instead of putting more money into the Jacobs EB I'd upgrade to a PXRB.

My dilemma now is that the PXRB limits back pressure to 60 psi and with my current cam I can make 75 psi, so the Jacobs will produce more braking power than the PXRB. (I have 103# valve springs).


I have been able to tune my 5.9 to idle pretty quiet, all except the vacuum pump. It would be nice to quiet it up a little more.

I see Geno's sells a HD pump that has a bigger "muffler" on it. Any experience with that? Who makes it? I like sticking to Cummins when I can, but this current pump sucks!!



I have also thought about adding an electric vacuum pump and tank. Anyone done this?


Cummins sells the OE pump for $403.



My other dilemma is that I occasionally don't get full brake engagement at higher rpms and I have to press the clutch, let the rpms drop, and then get back into gear. While the motor was being rebuilt I inspected the brake and it wasn't sticky and appeared to be working properly. I assumed maybe the pump was failing, but I still have the problem with the new pump... so really it's either the spring in the brake is too strong or the solenoid. The solenoid is $367.84!!!!

So, there is my dilemma.


I do have my original pump in the garage and will likely throw it on tonight, but that's not my long term fix. It has also been sitting for just over 3.5 years so that may be an issue as well.

 

[mwilson]

Mine Jacobs pump turned noisy and lost vacuum about 3 years ago, I replaced the diaphragm unit with Geno's Heavy Duty version. So far, so good.

I don't know if your noise is the same symptom, but mine was loud enough to scare me into putting my bypass belt on until I got home and ordered the new rear section.

https://www.genosgarage.com/product/GOULD-GG09-HDDIPH/engine-rebuild-kits-3

 

[AH64ID]

No my noise is the pulley bearing...figures that it's bad and the diaphragm is good.

My dad's diaphragm failed 4 or 5 years ago and I do know the sound you are talking about.


I spoke with Pac and there ins't an option for more than 60 psi...

I also spoke with Jacobs and they have been out of parts for 3-5 years on these trucks. He thinks I might have a bad diaphragm in the brake actuator.

 

[mwilson]

There are two 12 Volt air solenoids used on the older Freightliner Trucks to control air fan clutch engagement. One is normally open and the other normally closed. I don't see why one of those would not control the brake in lieu of the $300.00 Jacob replacement.

A06-26661-000
A06-26661-001

At another location today and tomorrow, have schematics drawn up by a tech in my notebook that I will dig out Friday when I return to Bangor.....

Parts diagram...

Engineering Diagram...

 

[AH64ID]

Thank you.

The old pump will go in tonight and I'm leaning towards a PRXB vs spending more money on the Jacobs. Eventually the Jacobs actuator diaphragm will fully fail (especially if it has a small tear now) and they are no longer made.

 

[mwilson]

Checked online and the Freightliner solenoid would be about $65.00 to $75.00....that would replace the Jacobs solenoid (99% sure it would work)...

 

[Motorhead]

John, I have had a PRXB on my '07, 5.9 since 2008. Only thing I would change that I already have done is don't use their wimpy compressor. I put a big, 100% duty cycle, Viair compressor up under the right front door area between the frame and body. I rubber mounted it and it is pretty quiet. I put a 2.5 gallon tank up under the right rear door.
I have not had one problem with the brake and actuator. It also brakes extremely well.

 

[AH64ID]

Thanks!

I already have a ViAir 450C hard mounted inside my tool box. Pac sells a pump-less kit that I have been pricing. I would add a 1/2 gallon tank, check-valve, and call it a day.

I swapped my old vacuum pump onto the truck last night and the noise appears to be gone. I disassembled the "new" pump and while I couldn't reproduce the squeak there is about 1/8-1/4" of end play on the pulley.

As much as I like the increased max backpressure of the Jacobs over the PRXB I think I am done spending money on the Jacobs setup.

 

[NIsaacs]

I have also thought about adding an electric vacuum pump and tank. Anyone done this?

This thread might help.

https://www.turbodieselregister.com/threads/259122-Anyone-using-an-Electric-Vacuum-Pump-for-Exhaust-Brake

Nick

 

[AH64ID]

This thread might help.

https://www.turbodieselregister.com/threads/259122-Anyone-using-an-Electric-Vacuum-Pump-for-Exhaust-Brake

Nick

Thank you.