J-K Ram Disc Conversion thoughts...

[mwl1967@xxxx]

Quentin and all,

Something you may or may not have realized is that your 
Ram K's remote mounted brake booster assembly contains a residual check valve 
in the slave cylinder. This is designed to maintain minor pressure against the 
wheel cylinders in drum brake cars. I have been told by several brake 
rebuilders that if discs are used on a system containing any residual pressure check 
valve that pressure will slowly build until the brake system just locks and 
stops the car at which point you'd have to crack open a bleeder valve to get 
going again. 

I have considered disc conversions for both my K's but have not 
decided what to do concerning several issues:

1) I don;t know how well or if the remote slave unit would function in 
the absence of the residual valve. Running a disc/drum combination would seem 
to cause a problem... Converting to 4 wheel discs and eliminating the check 
valve would seem to make sense except for the fact that we're stuck with a 
single reservoir master cylinder.

2) The single reservoir master cylinder may or may not have adequate 
volume to run disc brakes. Additionally, converting to a later model, manual dual 
circuit master cylinder would not solve anything since how would one plumb 
the dual lines into the remote booster which is only desinged for one circuit 
ie: one in and one outlet . . . I suppose you could run a line , without power 
assist to the rear drums and run the front disc line through the booster 
assembly for assist but it seems a little sketchy. 

Remote booster / slave cylinders are still available from Midland and 
used in large truck applications. Perhaps they make a dual circuit unit which 
could be adapted . 

Another thought... I had once heard that todays master cylinders , 
either new or rebuilt, don't contain residual check valves but new, currently 
available wheel cylinders do. If this is the case then you may be able to run a 
disc/drum combination with no check valves in the system other than in the 
rear drum wheel cylinders. 

At any rate... lots to consider ... hope I didnt muddy the waters too 
much

Mike Laiserin


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