Review on 🔧 Mityvac MV8500 Silverline Elite Automotive Test Kit: Ultimate Diagnostic Tool for Engine Performance, Brake Bleeding, Fluid Transfer, and More by Adam Abner

BLUF: Yes, the design of the pin that tensions the piston rod can be improved, but this problem is easy to solve and I'm going to show you how to do it. Now an overview. If you're like me, before you buy a product, see what percentage of reviewers have given it a star. Then look for common themes. The common feature of this product is the famous safety pin which tends to fall out of its hole causing a lot of frustration. Many users are also frustrated because they find it difficult to replace the pen even if they find it on the ground after dropping it. Otherwise the pump works perfectly. So here is the solution. You will need a small vice (pliers), some thin rubber or cardboard and some contact glue (see last picture). A woodworking clamp will help but is not necessary. Steps: 1. Squeeze the pump to the end of the piston stroke and lock the pump in place (see first picture. You can use your hand, elastic cord, woodworking clamp or whatever you have). 2. Wrap a thin layer of rubber around the piston rod to avoid damaging it and clamp with a vise. This prevents spring return. (See second picture). 4. Remove the woodworking clamp or whatever was holding the movable arm in place. At this point it is easy to remove the moving lever that exposes the roll pin (see third image). In my case it looked like the roll pin was quite tight in the hole (enough friction), but I can see how manufacturing tolerances and temperature variations can reduce the friction between the pin and the inside of the hole. So I took a tiny bead of contact cement and applied it to each side of the barrel where it meets the pin. BINGO. The friction between the pin and the hole is enough to prevent the pin from falling out until pushed out of the hole. If you need to rebuild the pump later, the contact cement resistance is relatively easy to overcome, so you haven't done anything that can't be fixed. Now you know this simple trick and can deal with a small design flaw. Four stars because this simple workaround should not be left to the user. Otherwise a practical dual-use pump.