70 Electra Master Cylinder

[jaxops]

I am preparing to replace the MIDAS master cylinder with a CARS replacement GM master cylinder. I read the notes about taking off the lines bolts with a special tool. Will I need to replace the brake lines as well leading up to the master cylinder even if they match up (which is probably a "reach" that they would match the original parts alignment). [color:"blue"]

[NTX5467]

Any time you remove/tighten fitting on tubular lines (i.e., brake lines, fuel line at carb) you should use what is called a "line wrench" to do that. They differ from a regular open end wrench in that they encircle about 3/4 of the nut instead of just on two flats as with a regular open end wrench. They will greatly decrease the chance of flattening out the hex on the nut so the line will not have to be repaired/replaced as a result. You can get them at Sears and they come in various sizes too.

As for replacing the lines, they should work "as is" unless they are kinked or bent already. There's enough give in the lines to compensate for minor differences in where the lines attach to the master cylinder.

There are also some little tubular devices called "self bleeders" that you screw into the new cylinder to get the air out of it before you attach the main lines. They screw into the same holes the fluid lines do, but will curve back into the reservoir to allow you to pump the brakes to get fluid everywhere inside the cylinder bores before hooking up the main lines.

I've found that you can many times use some light and quick brake pedal depressions/releases to get the last little bit of air out of the guts of the cylinder. Might not work all of the time, though, if there's very much.

As always, compare the replacement with the existing cylinder before installing it.

Enjoy!

NTX5467

[Guest brh]

Try "bench bleeding" the master before you install. This is when you fill with fluid and pump a couple of times before you make any connections, if you get all the air out before hooking it up sometimes you can get lucky and not have to bleed the lines. Get those line wrenches they are worth it!! The only time I have had to replace a line is when the nut was rusted to the tubing and twisted the line, if they are in good shape I don't think you'll have much trouble. Good luck.

[Guest 70 Electra]

Be advised that all flare nut wrenches are not created equal. I have a Craftsman set I'd used for YEARS and they generally worked OK. Every now and then I'd round off a tube nut and wrote it off to the fact it was just a tight one. <img src="http://www.aaca.org/ubbthreads/images/graemlins/mad.gif" alt="" />

I have since learned that this is a case where the Snap-On product is clearly superior. Apparently the shape of the opening in the wrench is such that it grips the nut better. In any case, I borrowed a set and was so pleased that I bought my own. Now I never round-off any tube nuts. <img src="http://www.aaca.org/ubbthreads/images/graemlins/smile.gif" alt="" /> It was well worth the bucks!

If you plan to work on things where the appearance of the tube nuts is important, I'd suggest investing in a set of the SnapOn flare nut wrenches and save the Sears ones for plumbing in the house.

(Sorry, I thought I posted this earlier, but I guess it didn't "take".)

[Guest brh]

Vote #2 for Snap-On had them for years and have never rounded a nut.

[jaxops]

Many thanks- I feel ready to tackle this now.

[Sgt Art]

Who makes tools for Craftsman? That topic came up the other day. I was thinking it was New Britain or maybe Blackhawk?

Up-date: I found out who makes Craftsman (and Matco) mechanic's hand tools. The company is named Danaher which is quite large and involved in a number of other businesses.