Installed Pacbrake - Air leak somewhere

[John Berger]

I got the brake on and working. There was a leak at the bracket. After loosening that up and maneuvering it around, I got it quiet, but from underneath the truck there is still air escaping somewhere and the only source I can find is at the adapter plate that mounts the brake to the back of the turbo. I can feel air back by the wastegate actuator arm and/or the bottom bolt. Is this normal? I'm not thinking so. TIA.

 

[Phil Stuart]

EXHAUST LEAK

John,



Did you make sure all 5 of the bolts were tight on the turbo adapter?Metal gasket in there too?If they are then the only other possible place is the exhaust pipe donut or the band clamp at the turbo connection.



I've installed three of these with no leaks. The trick is to line up the brake with the turbo,install band clamp,but leave the band clamp loose enough so that it still stays together and you can swivel the whole thing around to line up the exhaust pipe donut flange.



Then when you get the two bolts threaded into the brake mounting holes for the donut,check side to side movement and make sure it's centered as best you can. Tighten down on the band clamp, then tighten the two bolts for the pipe evenly.

It's a matter of these two being lined up properly without any undue stress on either, or you'll end up with a leak for sure.

Hope this helps,



Phil

 

[John Berger]

Phil, that sounds like my problem. I was very careful about tightening up the bolts, but I could have missed on one. I think I'll "reinstall" the brake tomorrow. I got tired of skin burns right around 2:30 pm. :{ FWIW, the brake is working very well. Thanks for the tips. It would have been nice to know them this morning. This was my first e-brake installation. Other than the leak, it went extremely well. Back pressure readings off of the temporary gauge were within spec. I peaked at 61, but solid readings engaging the brake at 2700 rpm were between 48-55 psi. The leak doesn't seem to be impacting the performance.



All in all, it wasn't a bad way to spend a Saturday morning.

 

[John Berger]

Well, no joy again this morning. The leak is still there. And it's still coming from the wastegate actuator arm at the back of the turbo housing. I can feel the air with the exhaust brake engaged. I don't know what other adjustments I can make. The exhaust pipe mounting bolts do not fill the entire hole they are designed for, now. There are two or three threads exposed on the flange on the turbo side and this was not the case before I installed the brake. There is no way they are going to tighten any more than they already are, so I am at a loss. Is there supposed to be a gasket between the turbo and the brake? I'll take the brake off and sell it if I can't solve this problem. I'd rather go without than drive around with an air leak. It sounds like crap when the brake is engaged. You can hear the air really obnoxiously from the sides of the truck, but not in the engine compartment.



I think what I'm going to do is unhook the exhaust system all the way back and see if I can get a better fit between the exhaust downpipe and the brake. Is there any adjustment on the actuator arm? That is definitely where the air is coming from. I laid under the truck and stuck my fingers right up next to it and it is not coming from the adapter plate as best as I can tell, it's coming from the back of that arm. Sorry for rambling and being repetitve. I'm thinking this thing through in real time. :-laf



Another nice thing: At least a fellow burns the same spots when troubleshooting the same problem. Where's the Crisco. :{

 

[John Berger]

Upon further review the problem seems to be the plate. I took the whole thing apart and used the old gasket. Same leak. With the truck on ramps this time, I had the wife start it and the problem is definitely between the plate and the turbo housing. Looking at the plate from behind, it's between the bolt at the very bottom and the bolt at app. 9 o'clock.

 

[Phil Stuart]

John,



When I removed the stock turbo elbow,before installing the adapter and new metal gasket ,I used some light emery cloth and a small hand held wire brush to clean the mounting surface of the turbo where the brake adapter fits to it to remove any soot residue. Then used a rag and carb cleaner to make sure the surface was absolutely clean. I used anti seize on the bolts for the adapter and exhaust donut.



Yes there's nothing worse than an annoying exhaust leak that's a bear to fix.



By the way,the brake itself,when engaged makes quite a hissing sound from the exhaust going thru the small orifice on the butterfly valve. I can't figure why you have a leak where you say it is. The metal gasket,when compressed should seal the two surfaces well (all bolts tight of course )



Hope you get this ironed out John.



Phil

 

[John Berger]

I thought at first that the hissing sound might be normal, as this is my first experience with an exhaust brake. But I know I should not feel a stream of air coming from that area of the plate/housing. I'll take it off again and try what you suggested. You say there is a hissing sound that you hear when the brake is engaged. I can hear that from the sides of the truck and when I crawl underneath, it sounds like it's coming from the exhaust pipe. The only place I feel air is at the location I mentioned. It's really hard trying to find the source of the noise.

 

[QRTRHRS]

Make sure your band clamp is clean and coat it with antisieze. That will help it seat and keep it from rusting fast over time. Have someone start it while you spray some soapy water around the joint. Work fast as it will quickly heat up the water turning it to steam.

 

[John Berger]

Problem solved

There actually was no problem. I re-installed the plate and I got the air leak to move up the plate a bit, but that is not the source of the hissing. It runs all the way through the exhaust pipe when the brake is engaged. I walked around the truck after completing the installation again this evening and you can hear the hissing sound all the way down the length of the truck and coming out of the tailpipe. I put a rag over the air leak at the turbo housing and that did nothing to reduce the hissing noise. I guess it's a characteristic of the brake. I'm not concerned about the air leak at the plate/housing. It's only present when the brake is engaged. The brake is good to go. Thanks to all who provided input.

 

[Texas Diesel]

That sounds normal to me, both my ebrakes (Jacobs & PacBrake) make a hissing sound when the brake is on.



Mine doesnt leak air by the housing but the is some carbon buildup around where the shaft comes through the elbow so I know ir must leak a little.

 

[John Berger]

Now that I know the hissing sound is normal, I'm working on my shifting technique, trying to keep enough foot on the pedal while shifting gears, not slipping the clutch nor activating the brake. Downshifting is a piece of cake. Upshifting... well let's just say I'm hitting it correctly about 50% of the time. Those times that I miss, the truck sounds like it's farting. This brake could be fun in the right kind of circumstances and it doubles as piece of mind when towing heavy.

 

[Phil Stuart]

Good job John!

I didn't think you had a serious problem from what you were telling me. Glad you figured it out



Now the hissing sound is normal while it's on and the noise is much louder without a muffler (ask me)!



I opted for the pedal microswitch, shifter switch and the on/off switch I mounted on the lower dash versus the delay via pin 20 on the ECM. I like more control over when it engages. the delay works fine for some but I didn't go that route.



Phil

 

[John Berger]

Phil, I really didn't want the ECM option, either. I like having direct control, as it were. I mounted the switch underneath the steering column. I had a hole to fill from a previous bright idea that didn't work out so brightly. The brake switch fits perfectly.