Them Brakes!

I recently acquired this 1970 S2 OTS. The vacuum assist on the brakes was not working. A little bit of testing and fiddling pointed to the possibility that the Reaction Valve was shot. So I replaced that and the problem went from bad to worse. Now the brakes lock up when the vacuum is built up. I have to loosen the screws on the Reaction Valve cover to release the vacuum so the brakes release.

I bought this shop manual from the JCNA Shoppe (B-J28WH E-type 3.8 & 4.2 Series 1 & 2. Huge combined volume covering all components in detail. Approx. 800 pgs, photos, drawings) and read through the relevant sections. Couldn't find an explanation.

Your thoughts, suggestions and experience would be appreciated.

Could the Master Cylinder be the issue? Is it not sending the appropriate response to the Reaction Valve?

Regards,
Raj

Submitted by SE98-32482CJ on Wed, 08/15/2012 - 06:13

Raj remove the reaction valve and see if you can ease out the MC piston --clean replace test. Good Luck (Raj the piston will present itself as about .25 inches and is directly behind the arm on the reaction valve. Good luck.

Submitted by NE26-62240 on Wed, 08/15/2012 - 00:04

Thanks George. Any suggestions on how to further diagnose this? Do I have to take the MC apart?

Thank you,
Raj