Ok, so now I am flat on my back under the coach, now what coach? Last week we talked a bit about the equipment and such, now this week lets follow the route that I take doing the job. In my case I start at the left front corner of Rover using my 4 foot square piece of plywood as ground cover. I have my drop light or flash light, rag or two, grease gun, clip board and pen, and am wearing safety glasses. Yep, a couple of pieces of sand in your eyes can spoil an otherwise good day under the rig. I also have an old baseball cap that helps keep the yuck out of what little hair that I have left.
Now under the rig there is more to do than locate the grease fittings, wipe them clean, and apply the grease with the grease gun until just a little comes out between the boot and the joint. Some manufacturers claim that you have enough grease in the joint when the rubber boot over the joint balloons out a little. They do not want to break the seal between the boot and the metal around it.
At the left front of the rig is the Pitman Arm. That is the arm on the bottom of the steering box that connects to a joint, like a tie rod end, and a rod that goes back to the steering arm near the wheel. Once you locate that check where the shaft comes out of the bottom of the steering box to make sure the seal area is dry. Ya, I know it is daylight, but don’t be afraid to use your drop light as shadows can change the way something appears. This is perhaps one of the hardest thing to get students in the shop to do, is admit that they do not have Superman’s eyes and need added light to see. If it is dry move on. If it is wet and dribbling it might provide a clue as to where all the power steering fluid is going that you add.
There are a couple of places that I ask for a bit of help when under the rig. When checking the joints on the drag link for looseness do so before lubricating them. The pressurized lubricant in the joints will hide any wear in them. Ask the helper to get in the rig and move the steering wheel (engine not running) a couple of inches back and forth. Watch the drag link joints for looseness. There should be zero looseness. Any looseness make a note on your clip board so that you can reference it when you get out from under neath. Check the tie rod ends and any other steering linkage.
On my chassis, an older Oshkosh, with leaf springs on the front end, there is a grease fitting at the front pivot for each spring. These are sometimes called shackles. As you add the pressure to the lube gun watch the pivot and see if it moves. This could indicate a worn pivot and a worn pivot will allow the front end to wander when on the road causing excess steering wheel input to keep the rig straight. If you are feeling venturesome grab about a 3 foot crow bar. Insert one end between the frame and the loop end of the spring. Ply the spring down. If it moves then the pivot is worn and should be replaced. Remember, do this before lubing the joint.
Now while still under the left front corner of the rig, look up and find where the brake pedal linkage comes down through the floor on a hydraulic brake equipped chassis. Follow it along and there could be several lube fittings on the linkage at pivot points before it enters the brake booster or master cylinder. Make sure that you get these joints lubed as they caused all kinds of grief on some of the old P30’s. The shafts ran dry and caused the brakes to stay partially applied wear out the pads and dropping fuel economy.
Time to move to the king pins at the outboard end of the axle. These allow the wheels to turn an arc so that the rig can be steered. On independent front suspension chassis there might be king pins on class A units but most class C units will run upper and lower ball joints. Again grease just enough so that a little grease seeps out of the rubber boots. If it is a ball joint watch as you pump the grease gun for movement of the joint. Any movement have your front end guy check the joint for wear or stay tuned and we will cover that in a another posting.
Again on IFS, check the inner ends of each of the arms that connect the ball joints or king pins and spindle supports to the frame of the rig. Some use grease fittings in there. Once this area is completed and you have done your safety check of all parts move to the right side. That is all the space for this week, but stay tuned and see what surprise I found under Rover next week.