Vintage Mustang Forums banner
1 - 9 of 9 Posts

·
Registered
Joined
·
1,620 Posts
Discussion Starter · #1 ·
After getting my front end aligned today the mech notice that my brakes are very weak and he offered to check them for me. He checked out a couple of things (its not the vacuum)and he says he thinks when I put on the new booster I didnt adjust the rod that goes into the master cyl correctly. He probably right I just put it on out of the box :( Can anyone tell me how/how much you adjust this rod? How do you know where to set it. More in/more out?? Opinions.

Thanks
JBauer4363
 

·
Registered
Joined
·
12,404 Posts
You mean to the M/C? Adjust it so you have a little play befor ethe booster hits the M/C.. don't know if it would give you 'weak' brakes, per say.. just longer until the pedal hits the master..
 

·
Registered
Joined
·
1,620 Posts
Discussion Starter · #3 ·
Ya to the master cyl. I have power front disc and they seem like they are not power. They are even worse that drum brakes. Even if I slam them on they will not lock up. Wont pump up. Pedal hard. We blead them, checked for air in the lines - none, adjusted the rear brakes, pulling 17 vac. The mech thought that the booster wasnt working right. I thought maybe I didnt have it adjusted right.

JBauer4363
 

·
Registered
Joined
·
1,184 Posts
Unbolt the master from the booster and slide it forward.
Use a paperclip or wire to check the depth of the masters plunger. your looking for the lenght from the mounting point to the masters socket where the rod sits.
Now use that lenght to adjust your rod out to match it and then shorten it by 1/16.

If you make it too long your master cyl plunger will not release the brake fluid.
 

·
Registered
Joined
·
1,184 Posts
Yes,
Improper rod adjustment will cause your brakes to not work properly, (rod too short will not give proper presure to wheels. too long and it will not allow the fluid to return to master res after petal applied)

1/16 - 1/8 in from rod end to master socket is about right clearence after master is installed to booster.

Added;
the measurement that you need is from the masters mounting bolts point to socket bottom.
Then use that measurement from the mounting surface of the booster to the rod end.
 

·
Registered
Joined
·
1,620 Posts
Discussion Starter · #7 ·
After taking a look at the booster and master cyl I now remember that there is only about a 1/4 inch of room in front of the master cyl and the booster studs are long so sliding it forward much could be a problem. If I remember right last time I had to remove the booster and the MC as a unit to get the MC out and thats a pain. Do those studs on the booster come out?

JBauer4363
 

·
Registered
Joined
·
765 Posts
How to accurately adjust the booster output rod to match your specific MC:

In link below: Go to Installation Instructions (in the yellow box on the left), Then go to "Master Cylinder Adapter Kits", then click on "MMBAK-2".

http://maximummotorsports.com/
 

·
Registered
Joined
·
8,685 Posts
There is also a procedure in the Ford Shop Manuals, assuming you have one of those ;)

I recently checked mine for adjustment, and I had to loosen the nuts that hold the booster to the firewall. Once the nuts were loosened quite a ways, I slide the booster away from the firewall so that it pointed up and towards the center of the engine bay. This allowed enough room to slide off the M/C from the booster. Installing the booster is a PIA because the 5 or so studs never align right into the firewall, so this way prevents having to remove and reinstall the booster.
 
1 - 9 of 9 Posts
Top