Can anybody confirm the size of the brake pipe unions on my Peugeot 307. I had to remove the rear caliper after fitting new discs as I could not shift the handbrake rewind pistons on the car. Managed OK with the caliper in a vice though. Problem was that when I went to try and undo the pipe into the caliper it was so tight that it felt like it was just going to snap or worse. So I disconnected further down the line and then managed to get the pipe off in one piece on the bench with the flats of the union still usable. But there are signs of dissimilar metal corrosion in the threads of the ali calliper(steel pipes)So I want to try a tap in there and see if it will work before shelling out for a new caliper. I believe the threads are M9 but am unsure of the pitch. I think 1.25 but could be 1. I have some new metric unions and have tried running the male into the caliper but it tightens up a bit. There are no markings on the unions though.
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pedrobedro
Man at Matalan
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M10x1 usually.
Having just micrometered a new union it measured out at 0.393in which equates to 9.9822mm so 10mm for cash. As to the pitch I have a tap and die set (good make) and tried the M10 x1 and it looked too coarse. The M10x1.25 looked more like it but I was reluctant to try on the car union. Now I have dug out a new union I can give that a go. Thanks for your replies.
pedrobedro
Man at Matalan
- Messages
- 13,104
- Location
- CX near Chesterfield
M10x1.25 is coarser than M10x1 which is the standard for metric brake unions.
I have double checked the new union after I found a metric screw thread gauge and yes it is a M10x1. The mistake I made earlier is that the tap and die set I have is a large one and has 1.25 gear on one side and what I thought was 1 on the other. But then realised that at M10 size the thread pitch changed to 1.5! Luckily using the new union I have managed to clean the thread up even though it was trying to skew off at the start. I have bought a new pipe though to ensure it goes on OK. Thanks for your replies though. It all helps.
