Issues With Reman'd Master Cylinders

[MatthewH]

Those that have had to replace your master cylinder in the last couple years, have you had issues with them leaking, and not lasting very long? Running a CUCV master/hydro booster on my M37, and have replaced the master twice now due to a leak, usually out the back side between the master and booster.
Both times they've been warranty return and replace. The new one is now leaking again. Should note they have literally no miles on them. Still finishing the build, get to where I want to drive it, find the leak, replace, and something comes up and it never moves, just gets pushed around the shop, or moved in/out, so the brakes really only get used to bleed the system, or once a month or so when I'm out in the shop, I'll pump the brakes a couple times to keep fluid moving, try to prevent the calipers from setting up.
I am using clean fresh DOT 5, and I'm getting the master's from local Carquest, which I believe are a Cardone unit.
Any chance its cause it just sits? Or just crappy reman'd units.

 

[oldolds442]

Sure sounds like crappy parts.... Haven't had a NAPA around for a number of years, but I'd try one of theirs...

Sent from my XT1080 using Tapatalk

 

[doghead]

Do they specify they are dot 5 compatible?

 

[diesel583]

I never use rebuilt, new are out there and the difference in cost is not worth the sacrifice in time and safety. I never have liked doing the job twice and to me brakes are kind of important.

 

[Tinstar]

That is the exact reason why I never use rebuilt parts.
Sure it's under warranty, but you are finding out that it's not worth the time and effort when you have to replace it again and again.
New units can fail of course, but usually not as fast or as often as rebuilt.
Buy brand new. They are available.
The higher price is more than offset by it not failing almost as soon as you install it.

I know not every part is available as brand new.
Some are rebuilt only.

Buy a quality unit and never look back.

 

[MatthewH]

I will have to check and see if they are dot 5 compatible. As for new vs reman, you guys are correct, new is better, and that's what I usually use when available. Have to see if they can get one, otherwise ill have to find one elsewhere

 

[nukem]

Dot 5 compatability immediately came to mind?

 

[desertfox]

Typical poor quality rebuilds. New have a nearly polished bore. Rebuilds use course stones which allows fluid to leak by.

 

[joshuak]

Good point on checking compatibility with DOT5.

The description for a new master cylinder from Dorman specfies: "All rubber components are of high-quality EPDM compound for resistance to glycol-based brake fluid".

Link to description from rockauto: http://www.rockauto.com/en/moreinfo.php?pk=966080&cc=1053021&jsn=572

I reached out to Raybestos and AC Delco. Raybestos response below, my email to AC wasn't answered.

It will be fine to use DOT 5 with our products.

Thanks

-----Original Message-----
Sent: Monday, May 1, 2017 2:15 PM
To: (BPI Raybestos Other) <bpiweb.other@brakepartsinc.com>
Subject: [External] Raybestos Contact Form - Technical Service

This is a request coming from the Raybestos website.
Viewer: joshua krueger
Service Type: Technical Service
Message:
Greetings,

This inquiry is in regards to the compatibility of your brake products with DOT 5 fluid.

I would like to use them in an upcoming project and would like to know your opinion on using DOT 5 and the following products:

Your Master Cylinder:
RAYBESTOS MC39435

Wheel Cylinder:
RAYBESTOS WC37290

The rest of the vehicles brake system is already using DOT5.

Thank you