trouble with upper ball joints, suspension blocks

[XLRONYX]

I'm in the process of replacing upper front ball joints on my M400. I bought new Noble top blocks and new QH ball joints (QSJ1184S). Problem is, the ball joints do not thread into the blocks beyond 1/4 turn. It feels as though they have different thread pitches, but a thread gauge measurement confirmed that both pieces are a 1.5 mm pitch, and the threads appear undamaged under the microscope.

My original top block has a set screw to prevent the ball joint from backing out, but the new block does not have that set screw. This makes me wonder if the parts are supposed to have an interference fit.

I need the new top blocks because the old ball joints messed up the block threads (galled).

Have any of you experienced this when replacing upper ball joints?
Can anyone confirm or refute that the "new design" is supposed to be an interference fit?

Thanks in advance for any and all help!

Jeff

[TuxMan]

Hi Jeff I had this problem turned out to be faulty threads on the ball joint , took the alloy block into the supplier and we went through 6 before we found some that fitted correctly !!! Might be worth a try :-) Tux

[XLRONYX]

TuxMan said:

Hi Jeff I had this problem turned out to be faulty threads on the ball joint , took the alloy block into the supplier and we went through 6 before we found some that fitted correctly !!! Might be worth a try :-) Tux

Sounds right - the machinist where I work said that the male threads on the ball joint didn't look good. I expect a die that size will be seriously expensive!

Jeff

[XLRONYX]

For the three of you that are interested [ ], I have now tried 4 different new QH ball joints in 2 different brand new top blocks, and none of them will thread together. Today the machinist said that he now thinks the block threads may not be cut deep enough.

Not sure if it's OK to name companies here ... , but James at SWLC is going to send me 2 more blocks that he has successfully pre-test-fit with ball joints in exchange for the pair I have now. James and Kathy have been very helpful, which is extra appreciated when nobody on your continent stocks the parts you need.

Jeff

[R0162]

Hi Jeff, due to the nature of the ball joints and blocks they are very easy to cross thread, i.e. you put them in they start to turn and then lock up due to cross threading, i have just also just replaced all my ball joints and i experienced this same problem.

The threads have long travel, so you can turn the ball joint a couple of times before it starts to bind and show any signs of cross threading, they are designed to be a very close tolerance fit, keep trying putting the ball joint in at slightly different angles until the threads bind properly, also if you have it in a vice, the blocks are not very thick walled, don't over tighten the vice or it might compress the block slightly which can cause problems, also heat up the block to expand it, this will help the ball joint thread in by hand.
The old ball joints came out, the new ball joints are the same thread, so it goes to reason that they should fit, it can just take a bit of technique and a few attempts.