Started getting some parts in the mail. I cut up the 94-97 pedestal today to fit on the brake as well as isolated feed/drain lines.

 

So the EPR on the pedestal crosses and dumps into the drain. I will be using this drain as part of the return. It just so happens there is a nice little drain hole. Removed enough material so I could get at it. Wouldn't ya guess, an 1/8" npt tap fits right in it. It is at an angle but threads in well. For now it is plugged as I plan on welding the leak hole for the actuator.

 

Tapped and plugged stock oil feed location. I will be utilizing the 1/8"npt port on the back of the pedestal.



Wanted to use the stock oil feed casting as it allows for the best position under the truck. Not exactly pretty but it tapped well.



Now that the pedestal is hacked up it needs welded, as well as a sweeper seal for the plunger.

 

Nice work @brokestroke . I'm not exactly comprehending the fluid paths based on the pictures though. Can you educate me please? How far away from functional tests do you think you are?

 

Thanks.
Still a little ways out from getting everything hooked up since it is a side project.

Drew a little schematic of the actuator.

Oil branches off the main feed and goes into the actuator body. With the EPR open oil flows through and heads into the EPR cross drain, from there into the drain trough. When the EPR valve closes it shuts off the drainage and pressure builds in the actuator chamber activating the EBPV. Planning on adding a T-fitting to the oil feed that dumps out below the EPR. The EPR drain will dump into the T-fitting and recirculate to the pressurized drain. This enables a full flow bypass when the brake is not in use. One of my worries is dealing with oil seap around the actuator seal. Hope it is leak free, if not I will rebuild. Also plan on making a seal for the actuator shaft so dirt and debris cant work its way in.

 

I have contemplated a way to seal the actuator shaft in the past. This open hole is the reason for EBPV failure/leaks. DIRT gets in there and especially here in the south - it goes 10 months (or YEARS) before its cold enough to activate. The first time it does, it pushes the piston through the dirt and destroys the seals. Often, leaking so bad the truck is not driveable.

I am impressed by your fab skills and respect your design - but this adds toooo many points of failure for me. Maybe consider valves at your oil supply/return points so you can isolate this thing in the event of a problem?

Why not source a 12v actuator to control the valve? (Its EASY to be a critic!! )

 

Add a silicone (for the heat) bellows on the shaft like the rubber bellows on brake caliper slide pins have? If it's long enough to cover the length of the shaft stroke (That's what she said. Beat you to it.) then no dirt will get entrained into the mechanism.
https://dynatect.com/product/protect...ature-bellows/

 

So if I understand the schematic right, the actuator strokes when the EPR closes off the path to the drain and pressure builds.Spring pressure retracts the actuator when the EPR opens back up. Since you have plugged the EPR drain to the trough, how is it going to relieve pressure when the EPR opens?

 

My shaft seal design will be pretty simple and hopefully effective.

First I will drill/tap the actuator hole
Get a 1/4"npt brass plug and drill out the center to slightly larger than the shaft. Now when the plug is threaded into the body the rod goes through the plug. Match the shaft diameter with the proper sized o-ring and then drill the inside of the pipe plug for the OD of the o-ring. Install o-ring in the plug (needs to be held in place some how) and re-install on EBPV body.


Planning on adding an on/off valve in case something starts to leak. I looked at a few 12v actuators and didn't really see anything worth trying. The best I came up with was a P7100 fuel shut off Solenoid but didnt seem robust enough, although similar in design to some 12v actuators on other exhaust brakes.

 

I think thats how it all works.

Going to install a fitting in place of the plug. Have the plug in it right now so it can be welded on.

 

It might be easier to use a compression fitting and replace the compression ferrule with a piston rod wiper.

 

Didnt think of that, going to look into it. A great way to retain a wiper or o-ring. If an o-ring fits it should works as a seal to keep oil in as well. Needs to be sized so it doesn't compress around the shaft too much when fully tightened.

 

Revisiting the exhaust brake idea. The main hang up has been how to actuate it without air and costing a fortune.

Not sure how well it will work but I decided to try out a 12v Cummins fuel shut off solenoid to acuate the flap. I know they are pretty strong and activate quickly, they are also pretty durable. Travel should be long enough and they even come with a little heim joint. Wiring should be a breeze as well as dialing in the correct back pressure. That is if it works at all.

 

Something like this.

 

Got it slapped together, it actuates very well. One concern is it has an internal spring that once it is closed it can be partially opened.