Brake help! Pedal goes to the floor…at first

[bigblue79]

I am hoping someone can help me, I am at a loss. Beginning of the winter my brakes stopped working. I would press the pedal down to the floor with very little stopping. I have since ended up replacing both front and rear shoes, drums, cylinders, and a few brake lines as needed. I have tried to bleed the system three times, I have good flow and no air at all four wheels. However when I press the brake it goes all the the way to the floor on the first press. After about 3-5 pumps it no longer is spongy or goes deep into the press. I am not sure what is next. Anyone have any insight?

[roverp480]

I had this issue on 10" brakes when I put the brake pull off spring on the leading shoe back in the wrong place, I connected it to the trailing shoe, so pushing its piston too far back in , meaning I had to pump the pedal a few times before I got a solid pedal . The spring in the piston should just balance the bottom spring pulling the shoe back allowing it to "float" just off the drum
Picture shows correct assembly ,courtesy of the Series 2 LR club forum. Front leading shoe to the left of picture, trailing shoe on the right
13958

[jimrr]

just in case: order of bleeding brakes: LF, RF, RR, LR.

[jvsimmons]

Good diagram! I got curious after seeing the diagram and inspected the rear brakes ( 10 inch) on my late Series 3 88. I found the upper spring attached to both shoes instead of the post below the wheel cylinder. If my configuration is incorrect, how does the upper plate of the rear shoe stay attached to the rear piston slot or not rub the drum when the brake pedal is not engaged?

[bigblue79]

I forgot to mention that I have a 79 Series 3 109 with dual brake system.

I am going to rebleed, for some reason I was told to start at the back and work forward. I never thought about the springs, I put them on the way the last person had so I better check those too. Thanks!

[vlad_d]

* If you have the dual line system, then your front and rear brakes are separate hydraulic systems. You won't see any benefit from rotating around while bleeding. Focus on each: front or rear.

* Bleeding the Shuttle valve(PDWL) can be a pain. I found the best way was to unscrew the switch mechanism out of the valve and center the valve manually with a flathead screw driver. You can have someone buddy press the brake pedal down while you hold the valve centered, ensuring that both front and rear circuits are open(keeping the Shuttle valve from closing off the side with the air pocket/pressure drop). Make sure to use a hose attached to the bleeder screw into a jar with fresh brake fluid. I had to leave the bleeder screw open while holding the Shuttle valve...so you want to make sure it doesn't suck back air at the bottom of the pedal stroke. The jar of brake fluid and hose make sure it can't.

* Do that for each side: rear. then front...about 3-4 times until no bubbles come put. Push through clean brake fluid until you can confirm the fluid you put in the MC is what's coming out the bleeder screws.

* The Shuttle valve can do its job and block off one side(the leaky/air bubble side). If that happens, you can either get a soft pedal as the valve moving just eats up any hydraulic pressure. Or, it can be stuck shut, and no amount of pressing of the brake pedal will push fluid to that closed circuit. It's doing its job...blocking off a compromised circuit. So, hold it open and push fluid through both circuits until it's centered by the fluid in both lines.

* I messed around for weeks going from wheel to wheel, bleeding. Nothing improved. As soon as I centered the Shuttle valve and pushed out the bubbles, and didn't let the system suck in any air...the pedal went rock hard and I had great brakes.

* 109 Series III should have 11" brakes with two wheel cylinders on the front. It will look different than the diagram below. But the springs will still need to be on a peg of the backing plate and then one the shoe. Never attached to both shoes. The rear brakes on a 109 look like the diagram, though.

* Braking power is 80% front brakes. FYI. If you have bad brakes, it's probably air in the lines, or worn pads. Rarely just the back brakes. You might not even notice bad rear brakes.FYI.

Good luck!

[roverp480]

Good diagram! I got curious after seeing the diagram and inspected the rear brakes ( 10 inch) on my late Series 3 88. I found the upper spring attached to both shoes instead of the post below the wheel cylinder. If my configuration is incorrect, how does the upper plate of the rear shoe stay attached to the rear piston slot or not rub the drum when the brake pedal is not engaged?

The spring at the bottom between the two shoes is enough to keep the rear shoe in position against the slot in the piston, and the spring in the piston is also pushing that out so it stays engaged. . With the correct springs both between the shoes at the bottom and in the cylinder ,the trailing shoes can rub slightly but is always being thrown off the drum in normal forward motion and is hardly noticeable. I fell into the trap of putting the long spring between the two shoes back in about 1968 on my first Land Rover, a 1949 model, and subsequently had very long pedal travel , and had to pump the pedal to get the brakes on.
As an aside the very first 1948 Land Rovers did not have an adjuster and only the spring between the two shoes at the bottom. The were supposed to be self adjusting just rubbing on the drum all the time , the leading shoe having a special shoe with spring pushing out part of the lining as the rub area . They were soon changed to the format used on the SWB brakes up to near the end of the S3 vehicles.

[jvsimmons]

First thing to do this morning is to move the upper spring on the rear brakes from the trailing shoe to the post below the wheel cylinder! Will also readjust the shoes. I have never liked the way my brakes work even after changing everything in the system. The pedal is hard and there is not much pedal travel but they just don't stop the truck like it should -- doesn't matter how hard I push on the pedal I could never lock up the wheels for a panic stop. I have a gradual stop so I have to leave a big distance between me and the car in front of me. Hope moving the spring on the rear brakes will help improve the braking, even a little.

[roverp480]

The brakes should be able to lock up the wheels, especially in a panic stop. I would check to see the linings are correct as some are harder than original ,designed for when LR fitted servos. The linings can get polished with lots of gentle braking . My father was very gentle on the brakes & it used to frighten me how poor they were when I drove his car . The first thing I did was to do a lot of heavy braking to get them working properly again . He would then ask me what I had done to the brakes as they were a lot sharper.

[jimrr]

The brakes should be able to lock up the wheels, especially in a panic stop. I would check to see the linings are correct as some are harder than original ,designed for when LR fitted servos. The linings can get polished with lots of gentle braking . My father was very gentle on the brakes & it used to frighten me how poor they were when I drove his car . The first thing I did was to do a lot of heavy braking to get them working properly again . He would then ask me what I had done to the brakes as they were a lot sharper.

it's surprising how some systems just need "exercising". There was a little old lady here who'd take her flat head V-8 to my dads shop now and then. He took good care of her but sometimes just had to take her car out and RUN it for she literally pretty much just drove it to church on Sunday. That car would be worth a pile nowadays, I hope it's still running for a affecionato somewhere.

[bigblue79]

Just wanted to give a quick update on what I have been able to do so far. I was able to clamp off all flexible hoses and got good pressure. Then released clamps one by one and checked, isolated, and bled each one (rear, left front, right front). I got good pressure and pedal. The isolated front vs rear and got good pedal on just front and just rear. Then when the whole system was free I had a soft pedal again. Going to try to bleed the shuttle valve next. Wanted to update just in case this helps anyone to narrow the issue down and help me figure this out. Thanks for all the advice!

[jimrr]

If you're confident you've removed all air and the pedal WILL stay positioned with your foot on it then i'd suspect something going on with one of the brake shoes but it can be hard to get all the air out sometimes. maybe try advancing the adjuster till the shoes are up tight and see where the pedal is?

[73series3]

Just got this issue yesterday on the way home from work lost all break pressure barley stopped after pumping the brakes a few times it would build pressure for that one press then the vacuum booster would pull the remaining brake fluid right into the intake manifold and let out a huge poof of white smoke from the exhaust pretty sure the master cylinder is bad going to just change both all my lines and servos are new waiting for the delivery after the holidays

[jimrr]

mine has at times got to where if you stab the pedal quick it'll develope pressure quick but if you push it down slower like casual braking it'd bottom out. something to do with the tipping valve probably and adjusters being too far un-adjusted front or rear. I post this for reference as although not quite the same it may be related.