I have 2 PreBs and one seems to be bending the recoil spring, the other seems good.

I'm not sure if it is the same one but I do have the original springs they came with and one is clearly bent.

When I referbished them I put all new springs in and I used 16lb springs from Wolff.

I'm sure most of the issue is due to the short guide rod but what to know if there is anything I can check before replacing the spring and then ruining another one.

The gun can still function and had not issues at the range. I didn't know there was an issue untill I was done and cleared the gun to go home. The slide had a stiff spot and had a kink upon inspection.

Any thoughts? Or is this common for PreB guns? I can try tapering the front end of the guide rod so it can't catch as easily on the spring. Other than I'm not sure what to do.

I have many pre-Bs and I have never seen a bent recoil spring.  Perhaps your recoil spring guide is bent?  

There's a guy in Florida who makes high quality stainless steel guide rods for the CZ-75.  Maybe you should try one of his guide rods.

https://ssguiderods.com/shop/cz/cz-75b-short-solid-stainless-steel-guide-rod/?nowprocket=1

I have noticed Wolff's Browning Hi Power springs are longer than factory. Makes them tougher to install and have a tendency to try and kink. Wonder if it is the same with their CZ springs.

Different rate as well as longer?

Not sure about that. I tend to just get mag springs from Wolff these days after seeing the difference between OEM and their recoil springs.

Out of stock right now but CZ USA's web store states that the CZ75B recoil spring is a 16 lb. spring.  The CZ75B and the Pre B CZ75 should use the same spring if it's the old style round wire spring.  Some CZs are coming out with the flat springs and I don't know if those fit the Pre B or the Pre guide rod.  Haven't tried one.

cz-usa.com/recoil-spring-75-85-9mm

I've been working on this so I'll give everyone an update. I tried putting a nice rounded edge to the front of the guide rod and smooth it as much as I could. I put in a new 14lb Wolff spring for each pistol. I used my belt sander to flatten the ends so they are more square.

At the range I only shot 1 full mag of 17 rounds and checked the springs. 1 looks unaffected and the other shows a slight kink in the spring. It looks like the spring is slightly untwisted right at the front of the guide rod.

I ordered 2 guide rods from SSGuideRods and they came in today. They look great and I like that they have a chamfer in the front.

I replace the kinked spring with a new one that is not squared off with the belt sander and both pistols feel much smoother. I've read that the Wolff springs are a little long and maybe wider than the factory CZ spring. The new guide rod does seem narrower, maybe it is just smoother.

I may order 14lb springs from Cajun Gun Works and see how they compare. In the end I think the rear of the old guide rod was rounded or not square and was easier to tilt out of line causing the binding.

I had to snip a couple coils off a 75B +power  Wolff spring to ease the racking pressure.  It is fine thousands of rounds later.

Every recoil spring I have purchased from Wolff has been longer than OEM. I quit buying recoil springs from them.