BAC Forum
General Boards => Technical Support => Topic started by: Michael Hannan on April 17, 2021, 02:53:54 AM
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I can't get my coach started right now and it needs to be moved. There is no air pressure so the brakes are all on. I understand that it's possible to put air into the air tank from an external source. Where does the external source connect to the air tank? I'd prefer to do this rather than caging all of the brakes. I'm asking incase the tow truck driver doesn't know where to connect.
Thanks
MJ
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On ours the air coupler is next to the bleeder valves next to the batteries and fuel filter. Plug in your compressor air hose there. Using two male air fittings coupled together. Same coupler the tow driver will have to use. Some coaches have it up front next to the generator
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Thanks Jim. I'll let them know to bring a coupler that will work.
MJ
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If the air input valve is the same one that can be used to attach a hose to inflate the tires then that didn't worked when we tried it today. I thought it was the place you described as there are also 5 other valves each with a turn key that releases air when turned. Maybe I have the wrong place?
MJ
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Michael, the tow truck driver will have to remove the drive line if you plan to tow with drive wheel down
or will have to put your motorhome on a platform lowboy trailer. Damage will happen to your Allison
transmission if driveline is not removed. The tow truck drivers are experienced in removing the driveline. Last note: look into your Allison transmission book and that subject is spelled very clear.
Dave Atherton Retired Caterpillar Mechanic
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Thanks Dave. Should the air tank have been filling with air when he connected his compressor? Also, I only need to have it towed about 10' right now so that work can be done between my coach and the bluff I am backed up against. Does that change disconnecting the drive line?
MJ
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Micheal
Towing it 10 feet won't hurt the transmission but to tow anything more than fifty feet you want to remove the drive shaft or axle shafts to stop the transmission from turning with the wheels .
You should be able to air up your tanks from the fitting in the service bay
Did I miss something Why does the coach not move under its own power maybe we can help you get it running to avoid a tow bill.
Eric
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Something like this might work you'd have to measure to be sure.
https://www.homedepot.ca/product/citruswirx-disinfectant-wipes-bucket-460-wipes/1001585585?eid=PS_GOOGLE_D29K%20-%20CM_E-Comm_GGL_Shopping_PLA_EN_Kitchen_Kitchen_PLA_EN__PRODUCT_GROUP_aud-766395132185:pla-343007891471&gclid=Cj0KCQjwse-DBhC7ARIsAI8YcWJX1If1PRKInv5cI-_qPnwdssHjDwbM_LXHboXl4BKIkJVIIqtYxr0aAmnVEALw_wcB&gclsrc=aw.ds
https://www.google.com/shopping/product/1958598988847951148?q=scott+disposable+wipes+bucket&client=tablet-android-lenovo-rev2&biw=1103&bih=690&tbs=vw:l,ss:44&sxsrf=ALeKk01IL_c0f9ANwT9Gv0vnDn62DRIgng:1618771220798&prds=num:1,of:1,epd:13794841275507372499,prmr:1,cs:1
Sorry I posted this to the wrong post.
Hope this helps
Eric
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I'm afraid that ,my lack of knowledge may have led to a seized engine. I have BCAA (similar to AAA) that will cover the tow. Thanks for the transmission towing info.
MJ
Micheal
Towing it 10 feet won't hurt the transmission but to tow anything more than fifty feet you want to remove the drive shaft or axle shafts to stop the transmission from turning with the wheels .
You should be able to air up your tanks from the fitting in the service bay
Did I miss something Why does the coach not move under its own power maybe we can help you get it running to avoid a tow bill.
Eric
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By seized your saying the engine won't crank over ?
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Yes that's right. I started it to move it. The check engine and engine trouble lights came on. It stalled out a few seconds after running. When I tried to start it again, there was a clunk noise like the starter was trying to spin but couldn't. I checked the oil and there was only a touch of oil on the bottom of the dipstick. I live in this full time and it hasn't moved in 4 years so checking the oil didn't seem to be important. Stupid me. My un-educational guess is that I seized the engine. This is all on me.
MJ
By seized your saying the engine won't crank over ?
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Micheal
Have you check for fault codes if you had a check engine light there should be a fault code which might give you some inside into your failure.
You can pull fault codes using the cruise control switches and check engine lamp.
Eric
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Not related to the question but if you can still see any oil on the dipstick, there is still a lot of oil in there. I doubt that seized anything. Think positive 👍
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William that's what I was thinking but his description doesn't sound good
I was hoping the codes could tell us if he had a low oil pressure code 24 , or wheather there may be something else wrong.
Eric
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Success on releasing the park brake by adding air with a compressor. So I have moved the required distance. No I haven't checked for codes yet. I'll have to pull up the procedure From my files and do so. Thanks everyone for the help in getting my this far. I'll check back with the codes. A new stater is still pricey but not as much as repairing a seized engine. Fingers crossed.
MJ
Micheal
Have you check for fault codes if you had a check engine light there should be a fault code which might give you some inside into your failure.
You can pull fault codes using the cruise control switches and check engine lamp.
Eric
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Ok, so I used to think I was pretty smart but over the last couple of days, not so much. I went through the fault code process and am confused with what I saw. So there was 4 flashes that I assumed were the initial system start. Then came 6 followed by 4 (64 right). Then 6 followed by 4 again (I checked 3 times to be sure). Then 7 followed by 5 (my fault code list stops at 74). Then finally there was 1 single flash then no more. I made a video of it but I think it's too large to post here if videos can be posted at all. So my confusion? Why two 64 codes and a mysterious 75 code. Am I reading the sequence wrong?
MJ
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Micheal
Are you sure that isn't a 46 and 47 and 51
46 = very low oil pressure
47= shut down occurrence
51= intermittent battery power to ECM
If that is the case you may be right as to the seizure.
But as William was saying the oil pan would have to be almost empty.
Or possibly an oil pump failure.
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It could very well be if there was an initial flashing of the light before the codes started. I read that the light would start flashing when the Resume button was pressed and held.
MJ
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What engine is in that coach?
Eric
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It's a CAT 505 hp C-12
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Micheal
At this point I would try to bar the engine over by hand if no go I would drain the oil and drop the oil pan and check for a connecting rod that can not be wiggled or moved on its journal it will feel tight compared to all the others once You've found the one you think is seized you can loosen the rod bolts and see if the engine will turn it it does then remove the cap and see how much damage you have .
Either way at this point your looking at a crank reground or replaced and new bearings and the effected connecting rod should be replaced or resized.
In order to do this the engine will have to come out and at that point a complete rebuild is in order.
Not great news
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I'll try those things. I figure $10,000 plus. Thanks for your help Eric. How does the engine come out. Does that back of the coach get removed?
MJ
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Ya the rear cap would have to come off to get the engine out.
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Gentlemen, my suggestion before you start anything more at this point take a oil sample from your
engine. The results of oil sample will direct you to engine failure. Personally it is very unlikely that
Your engine has to come out of your motorhome. The Caterpillar C-12 engine is a very strong engine
that has a excellent track record. It is likely that a cylinder may be full of diesel fuel from bad injector
Leaking off filling cylinder and yes you would not be able to turn engine over.. if perhaps it is determined engine has to come out. A simple cut on both sides on bottom of cap both sides of assess
doors will allow you to remove engine straight out the back and second thing remove engine with Allison transmission connected will save you real lot of money in labor. this is the way Dave Diesel has
Changed out and removed engines . After engine reinstalled replace fiber glass bottom piece that
allowed for removal access. Last I have used fork lift with extended forks that it is very cost effective
That will allow engine to come out the back real easy. Dave Atherton Retired Cat Mechanic
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Thanks very much Dave! We are indeed fortunate to have your expert knowledge here. We have an authorized CAT repair place near here. I'll be sure to pass on your ideas to them as I'm sure this may be their first RV CAT surgery.
MJ
Gentlemen, my suggestion before you start anything more at this point take a oil sample from your
engine. The results of oil sample will direct you to engine failure. Personally it is very unlikely that
Your engine has to come out of your motorhome. The Caterpillar C-12 engine is a very strong engine
that has a excellent track record. It is likely that a cylinder may be full of diesel fuel from bad injector
Leaking off filling cylinder and yes you would not be able to turn engine over.. if perhaps it is determined engine has to come out. A simple cut on both sides on bottom of cap both sides of assess
doors will allow you to remove engine straight out the back and second thing remove engine with Allison transmission connected will save you real lot of money in labor. this is the way Dave Diesel has
Changed out and removed engines . After engine reinstalled replace fiber glass bottom piece that
allowed for removal access. Last I have used fork lift with extended forks that it is very cost effective
That will allow engine to come out the back real easy. Dave Atherton Retired Cat Mechanic