Fluid Follies

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Max Welton
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Joined: Mon Jun 03, 2002 12:01 am

Fluid Follies

Post by Max Welton »

I have no idea of the condition of any of the hydraulics in my 67 so I decided to redo all of it and switch to DOT-5 fluid. I've installed new calipers up front, new wheel cylinders out back, a new master cylinder and steel braided flex lines on all four corners. I thought I was doing OK until I poured fresh fluid in the reservoir and it ran right back out on the floor. I forgot to screw the new switches into the master cylinder. Today's kitty litter moment.

Time to step away for the evening. Should be able to bleed the system on Friday.

Max
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raygreenwood
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Re: Fluid Follies

Post by raygreenwood »

I hope you cleaned all of the calipers, lines, hoses and master cylinder out with denatured alcohol. The factory assembly lubes for DOT 3-4 systems are not compatible with DOT-5 and vice verse (unless the DOT 5 assembly is using straight silicone...very sparingly).
Ray
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Max Welton
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Re: Fluid Follies

Post by Max Welton »

The entire system (with the exception of the hard-lines) is brand new and has never had fluid in it.

Max
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sideshow
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Joined: Mon Oct 27, 2003 11:00 am

Re: Fluid Follies

Post by sideshow »

That doesn't mater, what was (if any) used as assembly fluid?
I am skeptical that vintage old school brake parts would have a DOT5 compliant pickling grease to insure shelf life.
Yeah some may call it overkill, but you can't have too much overkill.
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raygreenwood
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Re: Fluid Follies

Post by raygreenwood »

sideshow wrote: Tue Mar 03, 2020 6:06 pm That doesn't mater, what was (if any) used as assembly fluid?
I am skeptical that vintage old school brake parts would have a DOT5 compliant pickling grease to insure shelf life.
Yes.....thats what i am getting at. Actually....even if you are not changing to a DOT 5 fluid....you should strip and clean all master cylinders and wheel cylinders with denatured alcohol. I have no issues with stripping calipers as well either but some people might.

It is unbelievable how much crap and grit are inside of these cylinders even from German factories. It takes very little to jam a compensation port flap open.

You could probably just pump denatured through them and then pump a little fluid through to clean that out right before install but I have never tried it that way.
When i was in high school....a dealer bought, in the box, new master cylinder used to be pretty damn clean. By teh late 80's or early 90's....they have all been filthy.

Ray
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Max Welton
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Joined: Mon Jun 03, 2002 12:01 am

Re: Fluid Follies

Post by Max Welton »

Well, that's not good news. :(

I did run a fair amount of fluid through the system when I bled it. Probably a cup or so at each corner. I'm hoping that flushed it out well enough.

And of course I just dropped the car off to the metal guy for body work and paint. It will be in his shop for the next three months or so.

Max
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