The most common problem is that the air pressure in a tire is low. The second most common problem are the hangers on the deck. They'll have a nut with a sort of ball and they'll fit in the suspension arm. Sometimes if you hit something hard enough they will dislodge and one will be jammed upwards and get stuck. If your deck has rollers, be sure that they are in corresponding holes.
If you've ruled this out, then what you'll need to do is find a nice flat spot so you can measure the blade height from the ground. The above mentioned suspension joints can be adjusted to raise and lower the side to side and in the front of the mower will be two links with adjusters that can be screwed in and out and will also adjust the side to side and the front to back height.
Check that you don't have a bent blade.
The hangers on the rear of the deck will be the ones to have the sort of ball fitting. There will be a nut and behind that nut is a sort of half-ball that allows the joint to pivot.
To remove the deck, there should be two cotter keys to pull that hold the rear hangers and one that has the lifting mechanism. You'll also need to slip the belt off the engine pulley.
Generally speaking I just lift the deck by hand to remove and install the hangers as it's more of a pain to me to mess with blocking it up. I don't think it matters whether you hang the front or the back first. Once you get one side on, the other is pretty easy. The Sears diagram is almost useless so I'm using the AYP diagram of the mower deck. It doesn't show any rollers.
First thing I would do is remove the blades. You can lay them together to check for a bend, they should rest perfectly one in the other. To remove them with the deck still attached you take a piece of wood and fit it so that the blade will jam against it and won't spin. Then use a wrench or impact to unbolt it. When you put it back together, use a little anti-seize on the bolt or nut.
Just keep replying to this same question and we'll find the way through. Thanks, PK.
1. Do you mean as to adjusting the deck? If so, I'll generally put the deck in the second notch on the height adjustment.
2. I think you can attach them to your message, I really don't know how your end works. I know some people use a service like Photo Bucket. I don't know how that works either.
3. There are a few springs on the deck, lift and drive assembly but I can't think of one that's only 3/8" in diameter. Does it have long hooks or short hooks on either end?
Check that the hangers are sitting level and that one's not bent. It sounds like you about have it fixed.
There is a spring with long hooks that goes on the idler for the deck but I think it will be bigger than what you describe. If the deck is functioning and the drive is functioning I don't know that I'd worry much about it. You probably should save it just in case.
You can cut with the deck as high as you like. I keep my bermudagrass at three inches which is the second notch on my old Murray rider. The cut quality can suffer so you need to keep your blades sharp.
There is an option to leave feedback when you've accepted an answer, that's probably the best way to let people know if you're happy with the service.
Thanks for using Just Answer and if you have any more trouble you can still come back to this question after accepting. I don't know exactly how long you can come back without starting a new question, so if you do have any other trouble, check back soon. Thanks again, PK.
Small Engine Technician
Owner of a full service shop and national parts sales website.