Brake pedal reserve distance on 1971 88” 2a with factory servo

[slowpatina]

I’ve looked around with no luck… anyone know what the brake pedal reserve distance is/should be on a late Series 2a with a factory installed servo? (I recently replaced the original servo). Thanks

[jimrr]

2-1/2 inches would be pretty tight, I think that's what the book says. when it gets to 5 click the adjuster and it'll do wonders.

[slowpatina]

Thanks, jimrr.

So, with your 2 1/2" distance in mind (from pedal to the floor when brakes are applied), I today measured that pedal height when stopped during a long test drive (with new servo, master cylinder, and, rear brakes 100% rebuilt). The unpressed pedal height (same as when I bought the truck) is 7 1/2", and when applying the brakes (engine idling/servo active) it pressed downward 3", being 4 1/2" from floor (the "reserve distance"). Pedal seems fairly firm, to the degree I chirped the rears a couple times when testing rapid/hard braking, and the reserve distance seemed same around 4 - 4 1/2"... ie: not much different than normal braking to a casual stop or at idle.

All in all, the braking felt very responsive and reliable. I was concerned on the first test drive a couple days ago though that the pedal moved down too far and went too low, but that perhaps seems not the case. Is it okay to consider the braking performance is acceptable with the reserve distance being almost twice that of what the book mentions? My mind thinks it shouldn't be an issue... but I've not done brakes several decades.

You mentioned "the book", which one? (I either missed seeing the measurement in books I have... or I need better books)

Thanks again.

[jimrr]

that brake measurement should be called 'free play' and is the distance from static positon to depressed (to the "firm" part) ....... 2-3 " should be ok with 3" about as far as like it. when I adj. my brakes I have the wheel jacked up so you can hear and feel the shoe engaging the drum and have it adjusted where you don't feel or hear it. if you think your brake might be tight "dragging"" your brake drum will get hot, it'll be harder to turn the wheel and in extreme you'll feel it while driving and you'll smell it, and see smoke maybe ......... so it's always better to have them ''looser'' than tighter. Landrover is pretty good about adjustment selectability so you can have the pedal pretty well ''topped up'' without dragging a shoe.
the BOOK" i refer to is the factory manual(s), on here referred to as the ''green bibile''. if you can find one there is nothing comes close in detail. you have to learn ''english'' sometimes but it covers everything down to bushing a cam shaft, adjusting ring/pinion and everything else.

[slowpatina]

Yes, the 'free play' aspect you mention is 3" until pedal is firm, and what seems called the 'reserve distance' is 4 1/2" from firm pedal (fully pressed) to floor. Total pedal height (unpressed) is 7 1/2". The clam shells are backed off just shy of shoes touching (spin tested on jack stands), and I set the servo's push-rod about 1/16"-1/8" away from touching the master cylinder push cone. Seems there's no need to tweak anything further, so when it stops pouring rain I'll do one more close-to-home test drive to break in the shoes a bit more, before doing a faster/longer distance run.

I don't have the green bibles but do have a 1969 version of the white covered LR workshop manual 'Part Two'. I must need new glasses if I missed seeing any pedal distance info. I'll take the truck on it's first lengthy jaunt... to the optometrist!

Thanks again for your input, jimrr.

[roverp480]

The Factory Workshop manuals changed colors a couple of times , my part one S2A is Green and part two which I purchased first is White.. The First Workshop Manuals were Green. The initial parts lists when the model was fisrt introduced were white with green writing and red Land Rover Zig Zag

[jimrr]

i've dreamed of having such a catalog as ""optional equipment"" for i've read since the 60's of options they use to offer, right down to the built in coffee maker....... or more probably tea?P480??

[slowpatina]

Back at this after thinking I was all set... but ended up having to purge front lines and replace them, then re-bleed, and now having issues with pedal height.

As a refresh, 1971 late 2A with servo. All new brake parts at wheels, incl drums. New DMC and servo.

System bled with vacuum pump on jack stands. Bleeder nipples not sucking in air. Solid, bubble-free outflow. Pedal high/firm with engine off. Upon start up, with foot on pedal, it goes down a bit as expected. Vac lines and servo check valve checked, seems all good. Clamshells adjusted. Reservoir level unchanged after ~65 test miles.

> When driving, pedal needs pumping ~2x until firm, else goes uncomfortably low to ~2.5" from footwell (being a ~5" drop from static, jimrr 's aforementioned 'free play'). Regardless, truck stops great, can even make it skid. No sideways pulling.

>> I'd like pedal to firm up sooner, and will re-re-bleed, so my enquiry this time is about shoe positions for bleeding. I've read numerous related posts online, and for every one saying have shoes snug against drums when bleeding (clamshells pushing), there's an opposite post saying have them backed off all the way ‘in’ so the wheel cylinder has less volume and potentially less air trap space.

>>> With what I know, shoes 'in' approach seems logical, but is there truly a best way or does it actually even matter much during bleeding?

Running out of bleeding patience, so any detailed input from experience much appreciated.

[jimrr]

of course having the cylinders shortened is always good but this Ain't no race car and i've never had discernable air issues doing it on flat and level ground. My advise is just assure yourself you've gotten any air out and drive the rig for a few months or say a couple hundred miles or a lot of brake use then bump those adjusters up till it's almost dragging the drum, re-bleed if you feel inclined and you'll probably be about like most any Land Rover on the road. on that vacuum bleeding, don't use max vacuum, if you have help and you've never done it the old way, try it, just make sure the pedal is still going down when you shut the bleed valve. and use slow motion on the pedal, be patient, and leave the cap on the resevour loose till you're done.

[jimrr]

ok, I'll accept it looks like you've done a good job so i was thinking maybe you have a high point in the brake line, a non-standard brake line that could have a loop going up in it that might possibly trap some air and that bubble just stays in the loop? another theory is the air is in the master cylinder. ford truck want you to bench bleed the master cylinder before you install it, i've never done this with land rover but it sure sound like you have a persistant bubble somewhere. check out that ''tipping valve'' on the brake system too. i've never had a issue with one but who knows?