Hya all,, this is something new to me, yesterday I thought I had a problem with my new parking brake chamber, checked it this morning, it is working fine, no problems, so now I'm concerned why the wheel hub is still turning on both sides, when in neutral with parking brake set, if I put it into gear the propshaft turns as it should and the hubs start to turn, I can see the prop turning its connected correctly to the prop and the hubs move but when I grab the hub as its turning I can stop it from turning, with ease, yesterday morning before I started engine the parking brake was set, and both hubs I couldn't turn at all, I released the parking brake put into gear everything worked, now I can't remember if when I applied the brake if hubs were still turning, and maybe I have broken something in the rear axle, I'm hoping at the worse it maybe something to do with the yoke that prop is attached to, the vehicle is jacked up on blocks so both hubs are spinning freely off the ground, they were just turning at tick over speed, I'm pretty sure that when I first connected the propshaft, I turned the hub whilst in neutral, engine off, and the prop turned, now it doesn't, and yet when in gear it does turn both hubs, but surely I wouldn't be able to stop it by hand so easily unless it's something to do with the fact that both wheels need to be on the ground before it functions properly, is there anyone that knows this system and would know what has happened or what I've done, and how easily I can fix it, thanks kev
How Does A Differential Work? (https://www.matfoundrygroup.com/News%20and%20Blog/How_Does_A_Differential_Work)
I am no expert on this, but can you turn the wheels with the parking brake set. If so the parking brake is not working. You should be able to stop one wheel from turning when the prop shaft is turning the wheels as the differential allows that.
Do you have the standard air brake system with maxi cans or one of the hydraulic systems?
I have the hydraulic brake chamber, which I have now checked and it is working but it doesn't seem now to be stopping axle from turning, but was speaking to a friend of mine who is a mechanic and he wreckons because I have it jacked up the axle won't work properly until I have the wheels back on and on the ground, that might explain why I can stop one wheel at a time either side when ticking over in gear, would you agree with that, he doesn't seem to think I have broken anything because basically it was only ticking over in gear and if the parking was activated the prop shaft would have just stopped, he said it may have been a different story if I had been driving on road at speed and operated parking brake,
You have a drive shaft parking brake then. So the wheels spinning in opposite directions when the parking brake is on is perfectly normal. When testing your parking brake use a strap wrench on the driveline.
Right. If the brake is on the trans out put shaft, the wheels will rotate opposite directions jacked up . Normal .
Yes your absolutely right, parking brake is on that is working I've checked. First I released the brake and I could turn prop shaft by hand, then I reset the brake to on and prop shaft was tight and I could see that the parking brake lever had pulled the shoes tight, and then I can turn one wheel as you said and the other goes in opposite directions, if I start the engine and put it into gear still with parking set one hub is turning forward and other in reverse, but I can physically stop the hub by hand as its turning with no force, so I presume both wheels have to be on ground before it works properly, thanks,
If you start the engine and put it in gear with the parking brake on the driveshaft should not turn nor the wheels. Does it have an automatic brake release when put in gear? Not a good idea to have that feature. Otherwise the parking brake needs to be adjusted tighter.
No it does not have automatic brake release, I have a cab switch on dash board, I'm a little confused cause earlier you said if parking brake is on then I can actually still turn hub and the other side goes in opposite direction if both wheels are off the ground which they are, but you just said if I start the engine and put it in gear, driveshaft and wheels shouldn't turn at all, I was under the impression that this would only be the case once wheels are on and on the ground where nothing turns, maybe that's what you meant after I've got wheels on thanks
Thanks for that, that is what it is doing, it's been up on blocks for months, while I have been working on it, thanks
No, the driveshaft should not turn with the parking brake on period. It has nothing to do with wheels on the ground. If the driveshaft turns with the parking brake on even in gear, the coach would roll down a steep hill with the brake on.
Missed the Oshkosh chassis in your first post and didn't know that your Foretravel has the parking brake on the drive shaft. My 89 Georgie Boy had an Oshkosh chassis with a drive line parking brake. IMO it's not not a very good parking brake. Yours may need adjustment as it may be holding only a little bit. I think mine had a knob on the end of the parking brake lever to adjust the holding power. There may be another way to adjust it too. When you get it off the blocks, see if it holds on a hill or with parking brake on see how much throttle it takes to get it to move.
Sorry I think we're misunderstanding each other a little, probably me, right, here we go again, parking brake is on drive shaft solid and tight not moving, but I can turn the hub on either side and the other side turns in opposite, direction, so I'm presuming that once the wheels are on and vehicle is on the ground then the wheels won't move, when I release the brake, and put vehicle into drive on tick over, both hubs turn in opposite directions, but I am able to grab one side as it is turning and stop it from moving with ease, thanks for your help it's probably me I may have made a mistake with my wording earlier, hopefully this will clear it up thanks kev
With the brake released , in the air, the axles may tend to rotate , engine on, due to band drag in the trans . Again normal .
If the brake is on , the drive shaft should not spin.
On the ground brake on. the bus should not roll. It may slide one wheel and move, if inclined on a slippery slope ..
In your reply #7 you say the parking brake is set and in gear. At that point the driveshaft should be locked and wheels should not be turning unless you mean by hand.
Kevin, what you are seeing is the normal operation of the differential. That's those gears in the big bump in the middle of the axle.
In normal operation the action of the differential gears allows the wheel on the outside of a turn to spin a little more than the wheel on the inside of a turn. With your drive shaft parking brake set, on slippery ground, one wheel may turn backwards while your rig slides down hill.
Art
Thanks for that info mutch appreciated, I like to understand how things work once I understand it helps then when it comes to repair things, I'm nearly 59 and drive trucks all my life for a living but if I had my time over again, I would have loved to be an hgv mechanic, thanks alot
Thanks for that info mutch appreciated, I like to understand how things work once I understand it helps then when it comes to repair things, I'm nearly 59 and drive trucks all my life for a living but if I had my time over again, I would have loved to be an hgv mechanic, thanks alot
Yes absolutely thanks
I think sometimes, when I write a message, I'm not very good with punctuation, and 1 sentence rolls into another, and it's surprising, how 1 message can be read differently by different people and can cause a bit of confusion, thanks for your help anyway yesterday kev