SUSPENSION ADJUSTMENT PART 1,CHECK BUS HEIGHT & BOGIE WEIGHT
Posted: Thu Oct 16, 2008 10:04 am
Please make sure to follow the instructions in the order that has been described. Do not skip the factory designed steps.
Alright, here we go guys, Suspension Adjustment Part 1 for Eagle Coaches.
I am going to break this up into 3 or 4 parts so that no one gets overwhelmed by this procedure. This will allow you to ask questions that you want answers to and to help you understand the procedure before moving on.
SUSPENSION ADJUSTMENT FOR EAGLE COACHES
SPECIAL TOOLS NEEDED FOR THIS PROCEDURE
3 each 12 TON BOTTLE JACKS
1 each 8 TON BOTTLE JACK W/3000 PSI GAUGE
1 each 1-7/8" WRENCH
LOTS OF PENETRANT
Make sure your tires are the correct size and properly inflated. Prior to starting any adjustment, make sure you lubricate all areas of adjustment using a good penetrant.
The correct ride height measured from the aluminum wheel flare edge down through the centerline of the wheel to the ground, should be 48 inches. Measuring from the bottom of the baggage bay tubing to the ground should be 14 to 14-1/2 inches. If you use the latter measurement, make sure you are on level ground. These are the measurements that were used for an empty seated bus. Since motor homes are carrying a load at all times, you may choose to set them an inch lower, 47 inches or 13 to 13-1/2 inches.
For every inch of threads on the adjustment rods, you will be able to raise the coach approximately 2 inches. Make sure you have enough adjustment to achieve the ride height desired. If you are out of adjustment, it may be time to replace that torsion bar. You can install longer adjustment rods in lieu of replacing the torsion bar; however, this may be a short term cure as the torsion bar may have already seen its better days.
Because of the geometry of the way a torsion bar with its fixing arms set in the bus, it is important not to let the coach settle to low before adjusting, as this will put more strain on your torsion springs and cause them to prematurely wear out. You want to keep the rubber inside the torsion bar wound up tight, kind of like stretching a rubber band.
The order of adjustment starts with the bogie or tag axle, then the drive, and finally the front. You will be adjusting the bogie or tag axle for weight, the drive axle for height and the front axle for weight and height.
STEP ONE, CHECKING THE BOGIE OR TAG AXLE FOR WEIGHT
You start be jacking the bus up to the correct ride height desired using the three 12 ton bottle jacks. Place two of the jacks at the rear outer most jack points and one at the front center jack point. Make sure you dial in the height desired and recheck before moving on.
The reason we are jacking the bus up with bottle jacks is because we want to find out what the bogie or tag axles are carrying at the correct ride height before making our actual adjustment. If you adjust the coach up to the correct height using the adjustment rods and then try to adjust the weight on the bogie or tag axle, you will change the ride height and then end up reversing your adjustment. This eliminates that extra work.
Next, take the 8 ton bottle jack w/pressure gauge installed to it and jack up the bogie or tag wheels underneath the end of the fixing arm as if you were going to change a tire. Jack until the tire just clears the ground. Read the pressure gauge. Because your gauge reads in psi, then you will double that figure to find the correct weight. Example, if your gauge reads 1500 psi, then you would double that and 3000 lbs. would be the weight carried on that axle. The correct weight should be 3000 to 3500 lbs. per side. Motor homes may want to carry a higher weight since they are carrying a full load all the time. It is important that you do not carry much more than 4000 lbs. per side since each bogie or tag axle torsion bars are rated for 5000 lbs. each. The reason you do not want to set it to the maximum is that you must leave room for increased loads when the coach is in motion. If you go through a large dip in the road and the rear of the coach comes down, it is adding weight to the bogie or tag each time you do that and if set to the maximum, you will possibly bend the inner tube of the torsion bar which will knock the wheel out of alignment and you will end up having to replace the torsion bar at that point.
If you are lucky and the weights are correct and no adjustment is needed, then you have accomplished the easy part of the procedure. If you are not so lucky and the weights need to be adjusted, then the fun will begin on my next post.
Alright, here we go guys, Suspension Adjustment Part 1 for Eagle Coaches.
I am going to break this up into 3 or 4 parts so that no one gets overwhelmed by this procedure. This will allow you to ask questions that you want answers to and to help you understand the procedure before moving on.
SUSPENSION ADJUSTMENT FOR EAGLE COACHES
SPECIAL TOOLS NEEDED FOR THIS PROCEDURE
3 each 12 TON BOTTLE JACKS
1 each 8 TON BOTTLE JACK W/3000 PSI GAUGE
1 each 1-7/8" WRENCH
LOTS OF PENETRANT
Make sure your tires are the correct size and properly inflated. Prior to starting any adjustment, make sure you lubricate all areas of adjustment using a good penetrant.
The correct ride height measured from the aluminum wheel flare edge down through the centerline of the wheel to the ground, should be 48 inches. Measuring from the bottom of the baggage bay tubing to the ground should be 14 to 14-1/2 inches. If you use the latter measurement, make sure you are on level ground. These are the measurements that were used for an empty seated bus. Since motor homes are carrying a load at all times, you may choose to set them an inch lower, 47 inches or 13 to 13-1/2 inches.
For every inch of threads on the adjustment rods, you will be able to raise the coach approximately 2 inches. Make sure you have enough adjustment to achieve the ride height desired. If you are out of adjustment, it may be time to replace that torsion bar. You can install longer adjustment rods in lieu of replacing the torsion bar; however, this may be a short term cure as the torsion bar may have already seen its better days.
Because of the geometry of the way a torsion bar with its fixing arms set in the bus, it is important not to let the coach settle to low before adjusting, as this will put more strain on your torsion springs and cause them to prematurely wear out. You want to keep the rubber inside the torsion bar wound up tight, kind of like stretching a rubber band.
The order of adjustment starts with the bogie or tag axle, then the drive, and finally the front. You will be adjusting the bogie or tag axle for weight, the drive axle for height and the front axle for weight and height.
STEP ONE, CHECKING THE BOGIE OR TAG AXLE FOR WEIGHT
You start be jacking the bus up to the correct ride height desired using the three 12 ton bottle jacks. Place two of the jacks at the rear outer most jack points and one at the front center jack point. Make sure you dial in the height desired and recheck before moving on.
The reason we are jacking the bus up with bottle jacks is because we want to find out what the bogie or tag axles are carrying at the correct ride height before making our actual adjustment. If you adjust the coach up to the correct height using the adjustment rods and then try to adjust the weight on the bogie or tag axle, you will change the ride height and then end up reversing your adjustment. This eliminates that extra work.
Next, take the 8 ton bottle jack w/pressure gauge installed to it and jack up the bogie or tag wheels underneath the end of the fixing arm as if you were going to change a tire. Jack until the tire just clears the ground. Read the pressure gauge. Because your gauge reads in psi, then you will double that figure to find the correct weight. Example, if your gauge reads 1500 psi, then you would double that and 3000 lbs. would be the weight carried on that axle. The correct weight should be 3000 to 3500 lbs. per side. Motor homes may want to carry a higher weight since they are carrying a full load all the time. It is important that you do not carry much more than 4000 lbs. per side since each bogie or tag axle torsion bars are rated for 5000 lbs. each. The reason you do not want to set it to the maximum is that you must leave room for increased loads when the coach is in motion. If you go through a large dip in the road and the rear of the coach comes down, it is adding weight to the bogie or tag each time you do that and if set to the maximum, you will possibly bend the inner tube of the torsion bar which will knock the wheel out of alignment and you will end up having to replace the torsion bar at that point.
If you are lucky and the weights are correct and no adjustment is needed, then you have accomplished the easy part of the procedure. If you are not so lucky and the weights need to be adjusted, then the fun will begin on my next post.