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JeepPuller · 12-20-2015, 06:18 PM

Anyone with experience on the ABS Modulator Assembly? The ABS Modulator Assembly in my 2003 34 FDDS Alpine is leaking from the bottom plate. I believe that is what this part is? It is located in the rear middle of the storage bay. It has 6 brake lines that connect to it. I have cleaned around the sides and am fairly certain brake fluid is leaking out through the 1 or all 6 screws or around the plate on the bottom.

I wonder if that plate can be removed and resealed somehow? Has anyone ever pulled this plate off?

Old Scout · 12-20-2015, 06:32 PM

"Congrats"--believe you are the first Alpiner with a leaking ABS pump....could be wrong, but looks like you will be the trailblazer on this one--keep us posted. Unless the leak is significant, most owners may never notice the leak. The location of the ABS assembly in most Alpines [above the sewer tanks] makes periodic inspection almost impossible.....

JeepPuller · 12-20-2015, 07:04 PM

How did I get so lucky? I will take a picture tomorrow. This pump is in the top rear of the main storage bay just in front of the sewer tank compartment. It leaks about a drop every time the brakes are pushed. There are 6 hex key bolts that hold this ~1" X ~6" plate to the bottom.

Old Scout - Have you ever bled your own brakes? I have a mityvac bleeder that has worked awesome on everything else I have owned, but I have not tried to bleed this Alpine using it. Was worried I need pressure bleeder to do it because it has ABS.

Beagle RC Air · 12-20-2015, 10:16 PM

Quote:

Originally Posted by JeepPuller

How did I get so lucky? I will take a picture tomorrow. This pump is in the top rear of the main storage bay just in front of the sewer tank compartment. It leaks about a drop every time the brakes are pushed. There are 6 hex key bolts that hold this ~1" X ~6" plate to the bottom.

Old Scout - Have you ever bled your own brakes? I have a mityvac bleeder that has worked awesome on everything else I have owned, but I have not tried to bleed this Alpine using it. Was worried I need pressure bleeder to do it because it has ABS.

The ABS assembly in the storage compartment can be a huge can of worms if it is leaking. After sealing the leaks, a software disc probably will be needed, along with a tech and the correct connecters/analyzer to get the modulator to push out the trapped air. I was unable to secure the correct analyzer when I needed one so a Kenworth shop

along with my disc got the ABS modulator bled. good luck!

beagle

Old Scout · 12-21-2015, 01:54 PM

Jeeppuller--sounds like Beagle is ahead of me with regard to dealing with the ABS module. Yes--I have bleed the brake lines on a number of Alpine coaches over the year, including my own. In doing a full four-corner bleed, I always "assumed" the fluid in the ABS was also being bled/exchanged. That is probably not the same as bleeding the module once air has been introduced, eg, replacing a seal or disassembly.

For the purposes of ensuring a complete bleed of the brake system, it requires that the wheels on all four corners be removed. It might be possible to bleed the outside calipers on the front wheels without removal but the rear wheel outside calipers are physically impossible to reach.

I just use a std manual/hand vacuum pump with a collection jar. Only trick is to ensure you close the bleed screws under vacuum when you have to empty the collection jar. Obviously, you also have to make sure the fluid level in the front bulkhead reservoir is maintained during the process. I begin the process by pumping out and replacing the old fluid in the reservoir before starting the 4-corner bleed. Normally, the process takes about 3 qrts of DOT 3.

JeepPuller · 12-21-2015, 04:51 PM

Thanks Beagle and Old Scout for the info and advice! It sounds like I will be looking for a shop in Albuquerque that can help. I really hate to pull this modulator and discover I can't bleed the system once replaced. I live on a hill with a very steep driveway that I can't even imagine having a brake issue on.

I will probably wait to do anything until after XMas. You guys enjoy the Holidays and I will post my results once I get it fixed.