| Author |
Message |
Ron Elkins (Captain_ron)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 28, 2005 - 6:58 pm: | |
I need a new compressor for my 8V71 4905. I was quoted $375 exch. and $475 exch. I've always been told I could get one for about $200 exchange. any recomendations? Or can I rebiuld it myself cheaper than the two quotes? and where do I get the parts? Also I need to flush my tanks
what with and how? What should I look for further in the brake system to check for problems or do preventive maintenance? |
Brian (Bigbusguy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 29, 2005 - 2:34 pm: | |
Yes you can rebuild them if you can rebuild a car motor you can do them .
I would make sure it does need a rebuild first .
The only way oil is going to get in is past the rings . And if your oil return is blocked the compressor crankcase will have too much oil.
You have a lot of air leaks compressor working to much.
You could take the disgharge line off and see how much oil is comming out.
Or it getting oil in from the intake line oil bath air cleaner over filled?
You could just re ring it pull off the head and cyl take it to a compressor shop have them run the hone in it to clean up the cyl walls put some new rings on .
But it probley easer to just buy a rebuilt one if your not good a rebuilding things like that you mess it up and your walking to your next show.
Brian 4905 Klamath Falls Oregon |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 29, 2005 - 2:37 pm: | |
yeah....I'd suggest buying one....no telling how many million time that piston has gone up & down in that cyl....they continue going up & down wheather they are pumping or not...do it right ...once |
Ron Elkins (Captain_ron)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 29, 2005 - 3:41 pm: | |
Ok how bout the sludge in the main tank? I just found out there is a tank in the rear that I didn't know about. It's probably full of sh#t. |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 29, 2005 - 3:57 pm: | |
just keep draining it...it will clear out..my Eagle has 5 air tanks...always drain them after 30 hours of operation |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 29, 2005 - 4:05 pm: | |
my training said after 10 hours of operation....but found not much in there by then...unless high humidity...if you still run out of Florida ...maybe evey 10 hours of operation would be better |
Brian (Bigbusguy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 29, 2005 - 9:36 pm: | |
The best way to put a end to the water and gunk is put a air dryer on like Bendex AD9 Look on eBay for them some good deals on them some times.
I would just keep draining your tanks until all the goo is gone. Look for all the tanks .
You have the two in one tank over the batts (2)drains on that one. The one by the rear axle , One under the seat, And maybe one behind the front axle the later 4905's had one there.
And if yours was ordered with the tag axle there is one more for that.
If the tanks was not drained for a long time there will be a lot of crap in them and it will look like the compressor is bad it may not be as bad as you think.
And if the 18 yr old high school drop out that work on the rebuild assembly line can do it you can easly do a better job.
Brian 4905 Klamath Falls Oregon |
Vin Prew (Billybonz)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 30, 2005 - 10:27 am: | |
Brian, If the compressor is blowing too much oil past the rings, will it fowl the desi cartridge? The Bendix site claims the AD-9 has a typical maintenance interval of four years.
How about the automatic tank drain valves?
Vin T6H4523A Dekalb, IL |
Brian (Bigbusguy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 30, 2005 - 11:52 am: | |
Bendix also says its self cleaning during the purge cycle . I think the maintenance interval would be shortend some if the compressor was realy bad. But thats for buses and trucks driving almost 100k a year. And $30. for a exchange cartridge every 2 to 4 years is not to much to keep your air dry and clean.
They say not to run other auto drains with the dryer I guess so you can see when the dryer needs service when you see oil and water showing back up in the air. Im redoing my AD9 moving it out of the engine room so it is not in the heat to the space by the rear axle , I also have 2 auto tank drains I may turn them off to see if any thing is getting past the dryer. The cooler you can get the air before it gets to the dryer the more water it will remove.
I would still do a smiple test with the compressor discharge line off and see if its pumping lots of oil . One on a turbo motor where the compressor is using the boost air if the turbo boost side was bad the compressor could suck oil in. But Rons 4905 if stock dont have that. The compressor also has to fight for its air over the supercharger sucking air in also and if the air filters or screens on the intake was blocked it would have a harder time and would be sucking under a vacuum and it could pump more oil then also. The compresors can last a long time the one on my old peterbuilt had over 1.2 mil miles on it when I sold the truck.
I would check some other things out before I would just spend $250.+ on a rebuilt one.
Brian 4905 Klamath Falls Oregon |
jimmci9 #2
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 30, 2005 - 12:46 pm: | |
in some caterpilar reference manuals ive got somewhere is the test for a compressor that is suspected of blowing oil out with the compressed air.... in this method of testing, you remove the 1" air line that goes to the dryer/wet tank and hold a piece of white paper 1" away from the fitting... have a 1" circle drawn on the paper... count the oil drops in the circle.... this will tell you how much oil is being discharged.... crude??? yes... scientific?? no... effective??? yes....i'll look for the specs if anyone is interested.... |
Peter Broadribb (Madbrit)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 30, 2005 - 1:04 pm: | |
Jim,
When you get a moment, I would appreciate those specs. Thanks.
Peter. |
Tim Jones (Torquester)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 30, 2005 - 8:18 pm: | |
Hi Ron,
I'd check with bendix before I did anything. Older Bendix compressors were not equipped with an intake check valve which holds a certain amount of back pressure in the cylinder after the governer unloads. This check valve kit is cheap and helps to keep the piston rings seated when the compressor is running in an unloaded state. The compressor is most likely to bypass oil when running in an unloaded state.
If you run the test the test that jimmci9 #2 is talking about I would check the results while the compressor is unloaded as well as loaded.
You did not say if you had an air dryer on you bus. If you do have a dryer, the oil that you are finding could be from a poorly maintained dryer rather than compressor wear.
As to specific answers to your questions:
"I've always been told I could get one for about $200 exchange. any recomendations?"
I haven't purchased one lately but that sounds pretty inexpensive.
"Or can I rebiuld it myself cheaper than the two quotes?"
That depends upon what your time is worth....by the time you are done chasing around for the parts and the machine work, I doubt it. I couldn't do it cheaper, but I live out in the boonies.
"and where do I get the parts?"
From your local Bendix dealer.
"Also I need to flush my tanks
what with and how?"
I'd simply use clean, dry air. Fill the systen and then drain the tanks numerous times. The only other way that I know of would be to remove the tanks, lines, valves, etc. and clean them one by one.
"What should I look for further in the brake system to check for problems or do preventive maintenance?"
Most of the damage has been done by allowing oil to attack the rubber components in the system. Unless you want to remove individual parts and rebuild them one by one, there is not much that you can do.
Disclaimer: The above information is to the best of my knowledge. It is not intended to be a replacement for the manufacturer's service manual procedures. Please proceed as you see necessary. I hope that I have been of some assistance.
Regards, Tim |