Fixed: Brake Master Change Nightmare, thanks to RX1900 (See pg4)

BrianM

BrianM

'74 - Blue Bomber
Team,
I need to change the brake master Cylinder on my '74 X1/9. Dropped the full assembly and while removing the break lines from the system in place, one line twisted off! Unfortunately I believe this is the hard line to the rear brakes. Not nearly enough pipe under the dash to add a new flare. Any ideas?

MS_small.jpg
 
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I had this happen on the clutch side, but I was able to flare under the dash. Maybe trace the line to a spot you can? CuNi brake line is very easy to work with. Beware of some of the stuff on Amazon. It's actually copper plated steel line that rusts days after installing. Ask me how I know...
 
You can fab a new section of line from the master to a point where you have better access. Connect the new line to your existing line with a brake union. You can use SAE double flare fittings on both sides of the union, but from the pics I'd probably source a new fitting for the bubble flare at the master. A union will provide a safe and reliable connection - a compression fitting will not, no matter how tempting it may be.

 
BrianM said:
I believe this is the hard line to the rear brakes.
Click to expand...
That's going to be a front line as it's off the split output. Presumably it's just a short link line that's sheared off? i.e. you've got a second (2 port) block that connects to the link piece and then goes off to the actual cylinder line - or is this not present on '74s? The threads on the blocks are not metric like later cars, but that's before my time 😬
 
Best to replace the clutch master at the same time. If it isn't bad now it soon will be. But if you thought the line nut on the brake master was stuck, wait until you try to remove the clutch line nut! All of these are very odd sized nuts but they are available.
 
As per @Ics19 - I think that is the short line from the right front on the master to the top of a block [really a union] and the line to the calliper comes into the bottom of this block. If so, an easy fix. Get yourself a pair of the fancy vice grips instead of a flare spanner too :)

But if you do not have this block you may have damaged the main line to the calliper. If so then I suggest you see if you can get this block and the short line - then do a new flare on the main line and you will have "updated" your lines.

www.midwest-bayless.com

Brake Line Jumper Distribution Block Union M10x1.25 ISO Bubble - 2-Lines (Fiat Bertone X1/9 1975-88) - U8

Brake Line Jumper Distribution Block Union M10x1.25 ISO Bubble - 2-Lines (Fiat Bertone X1/9 1975-88) - U8
www.midwest-bayless.com www.midwest-bayless.com

www.midwest-bayless.com

Brake Line Jumper at Master Cylinder - Medium (Fiat Bertone X1/9 1976-88) - OE NOS

Brake Line Jumper at Master Cylinder - Medium (Fiat Bertone X1/9 1976-88) - OE NOS
www.midwest-bayless.com www.midwest-bayless.com
 

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It was 25 years ago and I think it was the clutch master, but I didn't like the access and I choosed the lenghtened the line by fitting a short line (6-8 inches) with flares and fitting at both ends. The idea of one more place where it could leak was in my concerns, but it is still there and not leaking. This is the same solution as @jimmyx is suggesting.
 
This is a '74, so there may not be a union for this line. From the photo, it looks to be the front left brake, so probably the easiest one to replace.
 
Whew, looks like I got off easy. I guess I have an early 74, since I have a direct LF connection and not the join block. The join block makes sense moving all the connections to the bottom of the assemble.

Parts ordered from MWB, $65. What a deal. Guess I might need a longer bolt as well?

Yes, I'm doing the clutch Master as well.

Thanks Guys, great info.
BrianM
 
BrianM said:
... Guess I might need a longer bolt as well?

Yes, I'm doing the clutch Master as well...
Click to expand...

Do your future-self a favor, and use threaded rod instead of a bolt. That will allow you to remove either master without having to drop the whole assembly.
That's something I never would have thought of myself, but was shared with me on this forum years ago.

Brian
 
Russe11 said:
use threaded rod instead of a bolt.
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Not sure this is a good idea. More correctly, yes it is a good idea with respect to the stated purpose and even with the whole shooting match out of the car, this would make it a nicer assembly to work with. But. These bolts are carrying critical loads and threaded rod is generally the lowest, nastiest, cheapest grade of steel. And, as it is fully threaded, you have reduced the effective loaded cross section.

If one master is gone, generally the other is too and there is the bush and rust clean up etc so I see it as better to drop the whole assembly - do the whole job on the bench and stay with the OEM bolts.
 
Russe11 said:
Do your future-self a favor, and use threaded rod instead of a bolt. That will allow you to remove either master without having to drop the whole assembly.
That's something I never would have thought of myself, but was shared with me on this forum years ago.

Brian
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Threaded rod for securing the master cylinders is not a good idea. Most common threaded rods are made of mild steel and absolute Meh quality.
This is a stressed part that cannot fail. Granted the engineering folks at Bertone/Fiat built in significant margin for mounting the master cylinders, this is not wise to replace a grade 8.8 bolt with a Meh steel threaded rod (sure there are B7 alloy steel and other non-common variants of threaded rod).

BTY, the bolted joint puts the cylinders in shear loading.. not tension. Proper mech design/engineering is to have no threads in the shear loaded area.. if a threaded rod is used, that will absolute violate this engineering convention and proper practice. Now ponder why the oem bolts have such a long non-threaded section..

As for effort saving with replacing the master cylinders.. ever try to wrestle one of these master cylinder out of the car without removing the entire pedal box assembly, it's actually More effort and difficult to try t do these cylinders in place.

If anything at all, replace the oem bolts with identical or better new bolts and prevailing torque nuts.


Bernice
 
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While the pedal box is out..

Take the pedals and related bearings apart, on a 74' be assured that plastic bearing and more will be well-knackered.
Fix/repair/replace as needed.

No surprise for mech parts that have been in service for ...how many decades.. now?

This is one of those do it now or deeply regret not doing this later.. like once it's all put back together.
Oh, replace the brake fluid reservoir hoses while you're at it.

Bernice
 
Do apply moly based anti-seize on the brake tubing nuts (tube nuts). This will go a ways to prevent stuck tube nuts in the future.


Bernice
 
Rupunzell said:
Do apply moly based anti-seize on the brake tubing nuts (tube nuts). This will go a ways to prevent stuck tube nuts in the future.


Bernice
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On the threads? Like 2 or 3 threads up from the flared end? Is nickel anti seize ok?
 
johnph said:
On the threads? Like 2 or 3 threads up from the flared end? Is nickel anti seize ok?
Click to expand...
Any anti-seize (nickel, aluminum, copper, …) is good, very thin coat wiped onto the male threads, no gobs or glops.
 
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