Community Forums

Gadget Man · 07-17-2008, 12:34 PM

I recently returned from a trip in the mountains. Before leaving, I serviced the pivot points on my Pac-Brake, as best as I could. I could not get the Pac-Brake to open & close by hand, so I lubed the areas that I could get to with an approved synthetic lubricant.

The first few times I used my brakes while descending the mountain, the coach made a loud whistling noise. I couldn't tell for sure, but it sounded like the Pac-Brake was possibly hanging up. The noise went away after 3-4 applications of the brakes. This has never happened before.

Anyone experience anything similar?

Craig

Gadget Man · 07-17-2008, 12:34 PM

I recently returned from a trip in the mountains. Before leaving, I serviced the pivot points on my Pac-Brake, as best as I could. I could not get the Pac-Brake to open & close by hand, so I lubed the areas that I could get to with an approved synthetic lubricant.

The first few times I used my brakes while descending the mountain, the coach made a loud whistling noise. I couldn't tell for sure, but it sounded like the Pac-Brake was possibly hanging up. The noise went away after 3-4 applications of the brakes. This has never happened before.

Anyone experience anything similar?

Craig

quikduk · 07-18-2008, 09:14 AM

Interesting. I always worry about this happening. We just got back from about 1-1/2 weeks of vacation and before we left, I liberally lubed the pivot points, shaft etc.

I found that I really had to work the Pac Brake while I was lubing it as the shaft and butterfly seemed to be sticking a bit and I am sure the rust on some parts of the linkage do not help. The more I worked it, the further I could get the shaft out of the cylinder. We had no issues with it but it still makes me wonder.

I know the Pac Brake lube is designed to last a long time but I now lubricate it before every trip. Since we go out for 3-day weekends quite often, it is cheap insurance IMHO.

I have been thinking about taking it off and sandblasting the rusting components, then having them Jet Hot coated. I think it happens due to the high temperatures and the cheap zinc or cad plating on these parts. The Jet Hot coating would cure this for ever so the next time I look at it, I'll take some pics and post for comments.

Gadget Man · 07-18-2008, 09:28 AM

I was uanble to move the mechanism more than an inch or so, which prevented me from lubing most of the shaft. It felt like it was being restrained by a heavy spring or something.

quikduk · 07-18-2008, 09:35 AM

I believe it is. This is the spring for the butterfly valve that is inside the tubing/hose.

The more I worked it, the easier it was to lube up the shaft but it still only moves out about 1" or so. You really need two people to lube the shaft and pivot...or a tool to open it up as leverage is what is needed and I didn't want to bend/break anything.

I'll post my pics this weekend (or Monday at the latest) so let me know how similar/different it is from yours.

Ken

SCVJeff · 07-18-2008, 11:53 PM

About the only way to open that valve is with a pair of channel locks. Thanks for the reminder..

Shaun and Amy · 07-19-2008, 02:02 AM

I've been having trouble with my Pac-brake as well. If I use channel locks and break it loose and lube it before I leave it will work, but not on the return trip home. You can hear it try to engage, but the flipper won't actual move. I'm thinking that it's getting stuck due to a build-up of soot in the exhaust pipe at the flipper location. I was thinking of taking it apart and cleaning inside the tube. Hopefully, that will fix the issue.

tmitchell · 07-19-2008, 05:16 AM

I have read that the best maintenance for an exhaust brake is to use it. Mine has been on full time since 3/04, when I bought my 2004 DSDP. When I am going down hill and don't want it to engage I feather the throttle.
I was in the habit of depending on my exhaust break so much that I didn't use my service brakes enough and they were starting to glaze. Now I try to do some fairly aggressive stopping with the service brakes during each trip.
Tom

Gadget Man · 07-19-2008, 05:55 AM

Someone in another forum suggested doing this when lubing the mechanism, to get access to the Pac-Brake shaft:

You must use a 12-volt dc jumper to activate the pac brake. Best to disconnect the electric plug, then connect a good ground to one pin and 12-volts to the other. That is the only way to operate the pac brake.

Anybody try this?

Craig

B.C. · 07-19-2008, 09:18 AM

Activating the Pac Brake can be done by disconnecting the air line to the unit and using compressed air to operate the cylinder. I use a rubber tipped blow gun to accomplish this task. A second advantage to using air is that you can apply a little lube to the inside of the cylinder while operating the pivot points of the mechanism.

Gadget Man · 07-19-2008, 10:36 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by B.C.:
Activating the Pac Brake can be done by disconnecting the air line to the unit and using compressed air to operate the cylinder. </div></BLOCKQUOTE>
I'm confused then, are they 12V or Air operated?

Craig

SCVJeff · 07-19-2008, 01:59 PM

Where do you set the regulator for the compressor?

quikduk · 07-21-2008, 07:17 AM

It is air and electric. That is why you have a dash mounted toggle switch. This switch operates a solenoid that engages or disengages allowing air to the cylinder on the PacBrake, either from your air system or a secondary compressor. As far as setting the regulator, I am not sure where it would be or if, in my case, there is one. The cylinder could be internally regulated.

FWIW, I use this lubricant and flood the lower right point shown, which is right above the butterfly valve and it's shaft. The rust "coating" I can see on a few components is what I will be looking in to removing in the near future. I also use the PacBrake almost all the time. I always use it on the freeways, on and offramps, hills etc. but shut it off if I am idling around through campgrounds so maybe that is why mine works.

http://www.pacbrake.com/index.php?page=maintenance

The new PRXB model has a secondary spring and a modified, ventilated butterfly valve. Apparently it allows a more even braking feel and operation and the Mfr. is offering a discounted rate on upgrading existing units...but the $740 price of admission is still too high for me.

http://www.pacbrake.com/index.php?pa...haust-brakes-2

Ken

quikduk · 07-23-2008, 07:14 AM

Here are the pics of my PacBrake.

You can see the areas that are lubricated. I lube the front and rear pivots for the air cylinder, the air cylinder shaft and the shaft that attaches the "porkchop" shaped cam that connects to the butterfly valve in the housing below. This is the point (where this shaft penetrates the housing) that I "flood" with the PacBrake lubricant. As I posted earlier, I use the exhaust brake for everything except idling through campgrounds and below 10 mph. It works fine...for now.

I hope this clarifies things for those that had questions. Oh, the line coming into the rear of the air cylinder is...the...AIR line...

but I couldn't see where it went nor where the solenoid was located.

BTW, you can see a small shaft to the right of the turbo housing. I believe that goes to the waste gate and I lubricate it as well. You can see how hot the turbo gets by the fact that there is no paint on it nor on anything directly connected to it. It would actually benefit from a ceramic coating like Jet Hot and if/when I need to have it rebuilt (hopefully never), I will have this done as it helps cool the turbo and related connections helping it last longer.

As a side note, this is why it is critical that the engine oil be changed more frequently on turbo-diesels than gas engines and why you should use a HD diesel oil. Dyno or synthetic doesn't mean much to me since I will change the oil out once a year. For us, this equates to between 3000-4000 miles. If we were traveling more per year, I would most likely switch to synthetic.

I also have found that the lubricating properties, viscocity and lifespan of the Shell Rotella 15w40 (and the Shell Rimula 15w40) to be better than the Delo400 I have been using so I may switch the next time I change out the engine oil. And for the Allison trans, I may be going to the Shell Donax Tx since it is approved by Allison and is quite a bit less expensive than the Transynd ($7.84 vs $10.35 per quart).

I would recommend that you buy from a bulk plant as it is cheaper than the normal stores which have a high markup.

Sorry about the digression into the oil rant...