Sprint Car Suspension
When racing any type of car everyone knows that races are won in the shop, meaning that if you don’t take the time through out the week and the off season to properly maintenance your car and its components you are more likely to have problems at the track. You are also at greater risk of something going wrong. Not only could you miss things that are broken, but if you don’t have fresh grease and things aren’t rolling as well as they should be you could be giving up valuable lap time.
A common thing people don’t often maintenance as much as they should when racing open wheel race cars is the front end. The front end bearing are sealed inside the hub and around the spindle, but sometimes dust can get past the lip seals and mix in with the grease and act like grit. This can cause premature bearing failure.
When you have the hubs taken apart look for any type of scarring on the spindle, snouts, and king pins. But before you take everything apart, put the front axle up on blocks and make sure that everything is spinning and moving freely. Turn the wheels back and fourth from both the left and right side tires and feel for anything that is hanging up or just not operating smoothly. If anything is out of the ordinary pin point where the problem is and make sure you inspect that area in detail.
You should also rock both front wheels from the top and bottom to make sure there is not too much slop to where the wheel rocks excessively. Additionally, you will want to spin the wheels and make sure they spin freely. Also try to move the axle forward and back and side-to-side to make sure that the rod ends in the radius rods and panhard bars are not worn out. If they move excessively you should find the rod ends that are the problems and get them replaced ASAP. Also rotate all the radius rods, panhard bar, drag link, and tie rod to ensure that the rod ends are not seized. I recommend doing these checks after every race, but the actual maintenance should be done every three to four races.
The procedure of actually doing the maintenance should be as follows:
- Unload the car out of the trailer and do your weekly washing after racing.
- Spray all the dirt and dust off of everything.
- Power wash the tires with simple green and get the car in the shop.
- Once you get done checking everything mentioned above get the front axle up on blocks to make it easier to work on.
I find it best to use the setup blocks that you would normally block the axle off of. At this point the tires should be off the car from washing. You will need to take the drag link and tie rod off the car to make it easier to disassemble the hubs. You can leave the panhard bar and radius rods on the car because there is no reason to pull the axle out of the car unless it is bent or find that is worn.
Once you have those removed take your steering arms off the top of the spindle. These are held on with four bolts that go through the steering arm and thread directly into to spindle. Make sure that they are not bent down or up, especially if you hit anything recently like a tractor tire or another car. If they are bent but only slightly you can sometimes bend them back in the shop vise or possible with a sledgehammer and some wood blocks.
I have used both methods and they both work depending on the severity of the bend. You can only bend them back straight so many times before the material becomes weak so try to keep track of how many times you have done this, to be safe just replace the arm if you can. Bending it back should really only be done if you don’t have access to another.
Now it is time to remove the hub from the spindle. Take the dust cap off the hub and there should be a cotter pin that goes through the spindle strut and holds a castle nut in place. Remove this pin and take the nut off, the front bearing should come out and the back bearing will captured by the lip seal. To remove the lip seal sit the hub on the bench supported by two wooden blocks on either side of the hub. Take a punch and put it on the inner race of the rear bearing and tap the bearing out going equally from one side of the bearing to the other. The seal and bearing will fall out the back of the hub.
Clean all the old grease out of the bearings, I like to use a parts washer. Spin the bearings in your hand and make sure they move freely and not gritty of jumping and make sure there is not much play in the bearing race. If it does not feel right, replace it. If everything is smooth go ahead and pack your bearings with a good wheel bearing grease. I recommend using Lucas Oil “Red N Tacky”, but any wheel bearing grease you get from your local parts store will do.
Install the rear bearing back in the hub, after cleaning the hub from all the old grease. Inspect the hub for anything out of the ordinary. To install the rear bearing flip the hub over on the bench and lay the bearing in the outer race installed in the hub. Before installing the lip seal make sure that it isn’t ripped and still has some press fit in to the hub. You should have to lightly tap it back in the hub with a hammer until it’s flush with the back face up the hub.
Inspect the spindle to make sure it’s not bent or doesn’t have any grooves worn in it. Put the front bearing back in and install the spindle nut. Run the nut snug against the bearing and adjust it until the hub spins free but doesn’t have excessive rock back and fourth. Repeat this whole procedure for both sides of the axle.
Next, you will pull the king pin out and clean it. When you pull the king pin the hub will come off the axle. Clean everything and make sure all parts are clean and there is no unnecessary wear. Do the removal procedure backwards and use a grease gun to grease the kingpin. You can now reinstall all your components and repeat your initial checks to make sure you did everything right and you should be ready to hit the race track!
