Dual Power Brake Booster and MC Questions.

[jp-]

I am finally adding dual power brakes to my Rover to increase the safety in emergency stopping situations. I now have all the parts, but have a few questions. I ordered a new 88" master cylinder (PLC 454) from our hosts and it has the exact body style (profile) featured here on Teriann's site for the 109" cylinder:

http://www.expeditionlandrover.info/dual_brake_conv.htm

I suppose RN just had the 88" MC made from the same body as the 109" MC to save tooling costs??? That part doesn't concern me as much as making sure that I hook this thing up right. My new MC has the larger fitting closer to the booster. Does the 109" MC have the larger fitting farthest away from the booster? Larger fitting always supplies rear brakes?

Now on to the booster, also purchased from our hosts (PLF 314). 180degs from the vacuum fitting is a threaded hole. Is there supposed to be a plug in this hole? If not, what goes here?

[siii8873]

Smaller fitting is the rear line, Larger fitting goes to three way for front brakes. There was a post a short time ago about the size of plug.

[jp-]

According to Teriann's site, on the 88 MC, the larger fitting supplies the rear brakes. Now I'm really confused.

[siii8873]

both my automec 88" set and RN 109" pipes are configured with small fitting to rear brakes and large fitting to front brakes.

[albersj51]

Im doing this as well, but I am using the MC from a 1985 ford ltd, which fits perfectly with a minor mod to the push rod. As for the threaded hole in the booster, the idea is to use the old one, but for us its an upgrade. Ive tried a 1/8" pipe plug, 3/8" unf and unc bolts...close, but not it. Trying some metric ones today. If I find the right one ill post it here. If you do, please do the same as its a PITA! im using the proline booster.

Are you running standard 88 front brake (10" ?) Drums or 109 (11" ?) Drums? I have 109's on my 88, so I was going to use the 109 mc before I went witu the ford.

[SafeAirOne]

Now on to the booster, also purchased from our hosts (PLF 314). 180degs from the vacuum fitting is a threaded hole. Is there supposed to be a plug in this hole? If not, what goes here?


A plug, unless you have the optional brake vacuum failure warning switch installed there.

[siii8873]

I think RN, maybe others have the correct plug.