Thread form on brake flex hose 2004

[xlrlist01]

Does anyone know for certain what the thread form is on the nipple connecting the brake line to the flex hose for a 2004 XLR?

I have a new Delco flex hose and it will not fit on the nut. I have bought a replacement nipple which states it is 10mm x 1mm and that will not fit into the new flex hose either. Measuring the new nut it is 10.4mm in diameter and has a thread form of very slightly more than 1mm. I am aware that manufacturers deliberately use a slightly incorrect thread pitch so as to create a locking effect, so it is 1mm effective. However, the new flex hose will not accept either the nut on the car or the new test one I have. Hence, what have Delco supplied? The flex hose is otherwise exactly correct, length, fittings at both ends.

As the flex hose Delco have supplied is a different thread size, does anyone know what it is intended for, eg a C5? (The part number is showing as correct, suggests a catalog error.)

TIA

 

[CNC]

Hmmm? Some possibilities, maybe?

Sounds frustrating. I do not know the metric dimension which you are questioning. But maybe these observations may help. Are you sure you are putting the correct hose end to the correct fitting end? I.e., turn it around? I assume you ordered the hose by 'year make and model' from a reputable supplier? My experience with this kind of thing is that assuming the diameter of the fitting end is the same visually, is the "thread pitch the same?". If you have a Metric and or SAE Tap and Die Set, (most likely it's Metric) there is a Thread Gauge in the sets to insert into the threads which is used to determine thread pitch. Looks like a little pocket knife with fold out blades. Possible you may be able to find a Metric Thread Gauge Check Tool at a local auto parts store. Napa most likely. Good luck with this effort.

Please post to let us know what you found out when resolved.

 

[xlrlist01]

Sounds frustrating. I do not know the metric dimension which you are questioning. But maybe these observations may help. Are you sure you are putting the correct hose end to the correct fitting end? I.e., turn it around? I assume you ordered the hose by 'year make and model' from a reputable supplier? My experience with this kind of thing is that assuming the diameter of the fitting end is the same visually, is the "thread pitch the same?". If you have a Metric and or SAE Tap and Die Set, (most likely it's Metric) there is a Thread Gauge in the sets to insert into the threads which is used to determine thread pitch. Looks like a little pocket knife with fold out blades. Possible you may be able to find a Metric Thread Gauge Check Tool at a local auto parts store. Napa most likely. Good luck with this effort.

Please post to let us know what you found out when resolved.

Thanks for replying.
I don't know about others, but apart from in-line flex hoses, I haven't seen a GM brake hose that doesn't terminate with a banjo fitting from models years back, 1960s? So, no it isn't possible to have the hose the wrong way around. The hose is the correct hose in every regard except the female thread form at the top.
The part number is correct, though I was in error that it was supplied by Delco, it was supplied by GM.
It is incredibly difficult to use a thread gauge inside the female thread form to get an accurate reading.
I suspect, but haven't yet proven that the hose has come with a UNF thread form. It looks finer than the metric 10x1.0.
I'll try to mould something into the female end and measure that.

 

[CNC]

I assume you still have the old hose?

Thanks for replying.
I don't know about others, but apart from in-line flex hoses, I haven't seen a GM brake hose that doesn't terminate with a banjo fitting from models years back, 1960s? So, no it isn't possible to have the hose the wrong way around. The hose is the correct hose in every regard except the female thread form at the top.
The part number is correct, though I was in error that it was supplied by Delco, it was supplied by GM.
It is incredibly difficult to use a thread gauge inside the female thread form to get an accurate reading.
I suspect, but haven't yet proven that the hose has come with a UNF thread form. It looks finer than the metric 10x1.0.
I'll try to mould something into the female end and measure that.

If you still have the old hose, and it threaded into the female end, could you use a metric thread gauge and check the male end? Then check that against the new hose? Just a thought.

 

[xlrlist01]

If you still have the old hose, and it threaded into the female end, could you use a metric thread gauge and check the male end? Then check that against the new hose? Just a thought.

The old hose is back on my XLR. I like to replace hoses after about 10 years, so it is hardly urgent.
The 'problem' is with the new hose, I know what the old hose is. I'm trying to work out what to order to get a hose that will fit, given the error with the ones supplied.

 

[CNC]

Understand

The old hose is back on my XLR. I like to replace hoses after about 10 years, so it is hardly urgent.
The 'problem' is with the new hose, I know what the old hose is. I'm trying to work out what to order to get a hose that will fit, given the error with the ones supplied.

Got it. Didn't know. So obviously there's no way now that the old one is back on to check the thread pitch of the one that works against the new one that doesn't. Good luck with figuring this one out.