Technical Ritmo Abarth 125/130 TC brake hoses

[Agip]

Hi all. I just bought some new hoses for the front calipers on my Ritmo Abarth but they do not fit.
My new Ridex 83B0360 hoses has 10x1mm tread.
When measuring the old hoses i looks like it's 3/8" x 24 UNF thread that is correct.
I have looked at several other suppliers and they all offer hoses with 10x1mm tread.
Has anyone else experienced the same thing? Where do i find the correct hoses?
I want standard hoses, not steel wrapped racing type.

 

[s130]

The original Fiat P/N is 5988077.

The 130TC Workshop Manual states:

Front Brake Pipes To Caliper Unions: M10 x 1 with torque of 1.1 daNm or 1.1 kgm

When I look that up then I see companies are listing thread as M10x1.

The original Bendix calliper pots are Fiat P/N:9938112 (s) and 9938113 (d). These are Bendix P/N: RL669207 and RL669208

Also from my personal notes:

Front Calipers
--------------
Bendix Parts 669207 and 669208

Service Kit:
FIAT P.No.9938110
Dust shield - Bendix P.No.471082
Piston seal - Bendix P.No.Red---White-White-Yellow

Budweg BCA0056G L/H (Renault 12 70-81 & Renault 12 Gordini)
Budweg BCA0057G R/H (Renault 12 70-81 & Renault 12 Gordini)
Budweg Caliper Service Kit BCK5425
Budweg Caliper Piston BCP5420

 

[Agip]

Thanks for your thorough answer S130.

Out of curiosity I bought two fittings with 10x1 and 3/8x24 UNF threads.

Only the 3/8x24 UNF fittings fits the 130TC calipers.

 

[s130]

Well this is really odd. Every "official" technical source I have states 10 x 1.

3/8x24 UNF is 9.53mm x 1.058mm

Thinking aloud ...... UPDATE!!!! NOTE I've just reread your post and am wondering if it is the 10mm vs 9.51mm that is stopping the starting or the 10mm does start to go in but the binds on the pitch? Anyway I'll leave the rest below as-is

The fluid seal is on the end of the fitting or via a copper washer on top.

9.53mm will definitely go into 10mm with a very slight wiggle/wobbly. The 1.058mm pitch is only slightly longer than 1.0mm.

1 / 0.058 = 17.24 so every 17 threads one would completely loose / cut over a 1mm thread. As the unions only have 10 threads (approx) then over the full length you would be half a 1mm thread out.

I'm wondering three possibilities:

1) Someone in the past when replacing the hose used and wound the 3/8x24 UNF union into the calliper thus effectively cutting a new thread
2) They tapped out/cut a new 3/8x24 UNF thread. For a tap this would be a dead easy cut and not really noticeable
3) 10x1.0 has always been wrong or correct and Fiat just used 3/8x24 UNF as this would be a fairly easy self cutting fit

The problem with going from 1.0 mm pitch or 24 UNF / 1.058 it is a one way journey.

 

[Agip]

You are absolutely right S130. It's the diameter that is the problem. The pitch is pretty close.
Picture 1: I have another set of 130TC calipers and they are the same. 3/8' OK and 10x1 does not fit.
Picture 2:The 3/8' does also fit a Uno Turbo caliper (10x1) but is a little bit wobbly.

My new brake hoses are made to seal in the end. Not as the origials with copper washer on top.
If the threads were ok the new hoses may seal in the end as the hole for the breakfluid is in the sentre on the calipper. If not i can remove the unthreaded end of the hose and use the copper washer. Let's see.

I was hoping someone out there with a 130TC had experienced this. I don't like to use force to make things fit

I have a 10x1 'thread tap?' so i am going to cut new threads. I'll give you an update on that.

 

[s130]

Thanks for the update @Agip

I'm really sorry but I don't have the old brakes hoses for our 130TC. I usually keep everything but sadly not these. I have the old calliper pots but my thread gauge is not going to possibly fit the aperture and I don't have either of the M10x1 or 3/8 x 24 UNF fittings in my stock.

All I can suggest at the moment is to do web searches on the Fiat P/Ns and Bendix and Budweg P/Ns I listed and see what other technical info you can find.