2 1/2 pumps on brakes any ideas??

[glbft1]

so we have replaced 2 wheel cylinders and brake shoes in the back adjusted to grab and back-off a little bit bled system and still have a funky pedal?? any ideas
When we clamp off the rear brake line have great brakes unhook back to a 2 1/2 pump deal driving my friends to drink over this one:eek:........ thanks for all the help!

[kevkon]

Too much piston/shoe travel or it needs further bleeding.

[brucejohn]

glbft1, you have a 109? What flavor, year, etc...? Power assisted, dual or single system, etc...

[TeriAnn]

so we have replaced 2 wheel cylinders and brake shoes in the back adjusted to grab and back-off a little bit bled system and still have a funky pedal?? any ideas


If you have a 109 I have a web page for you. If you have an 88 ???

Whatchgot???

[Jeff Aronson]

Greg,

When you installed the new shoes and cylinders - two per side in a 109 - did you have to wrestle the brake drum over the shoes? It should have been a tight fit. If it slid right over without having to press the shoes together at the cylinders, you might have a brake drum that was turned once before you bought the Rover.

If the brake drum has been turned too far, your brake pistons will have to travel too far to get a firm pedal on one push. Your manual has the right dimensions for a brake drum; measure it and see.

The firm pedal with the rear clamped off tells you the issue is in the rear brakes. You and Walter know the bleeding drill all too well, so I'm confident you're bleeding it correctly. Try the brake drum measurement first; if you don't have the dimensions, then pull a front drum off for comparison. Remember to measure both rear drums.

Lastly, what happens to the pedal when you don't back off on the adjusters? Do you still have the multiple pump issue?

Jeff

[glbft1]

the 109 was a mod 1971 2a rovers north import used to be a ambulance but rn changed the body.. when i put the drums on had to work a little but generally slid on.. no shoe compression needed.

[brucejohn]

I went back and read your other post too and I am still trying to figure out which brake system you have.
Do you have a servo? If so, mechanical or hydraulic?
Which master cylinder did you just install?
Was it the same style you removed?

The IIa green bible doesn't mention a dual system so I assume you have a single one, is that right?

I know it doesn't seem relevant since you have "located" the problem in the rear portion of the system, I sense we are missing something the details may help us help you though. Would you mind filling in the gaps?

[glbft1]

its a single line no servo, replaced with a new master cylinder same size.
have also replaced both wheel cylinders and shoes in rear,,,thanks for all the help

[brucejohn]

Okay. Just to see if we are all on the same page:

You have a IIa green bible.

Your IIa has one wheel cylinder for each wheel, not two in the front, one in the rear.

For some reason you felt the master cylinder needed to be replaced. You replaced it with the same that was in, we can only assume that was the CV style. The system is a single line with no servo. You can find no leaks in the system, the flexible hoses appear to be in good shape.

After replacing the master cylinder you bled the system per the instructions starting at the closest wheel cylinder and working away from master cylinder, using the funky pedal push pattern (which I had never seen until you brought this up and I read the instructions in the green bible) and a bleed tube inserted in brake fluid as suggested for the CV style master cylinder in the green bible.

Next your replaced the rear wheel cylinders and pads. Are they 10" or 11" rear wheels? They have one adjuster at the bottom or two adjusters, one for each pad?

You rebled the system same as before following the funky directions.

Now, after several attempts. Clamping only the rear system off, the brakes work and pedal feels perfect, though if you clamp the front off the pedal takes 2 to 2-1/2 full strokes to build solid, not spongy pressure. Essentially, the pedal is the same as before replacing the wheel cylinders and pads.

I am just having trouble getting to two full strokes of the pedal just in the rears if everything is right and since the system is not working I assume we are missing something.

Sorry if I am being annoying, just trying to help.

[TeriAnn]

the 109 was a mod 1971 2a rovers north import used to be a ambulance but rn changed the body.. when i put the drums on had to work a little but generally slid on.. no shoe compression needed.

If you get the rear shoes installed in the wrong locations the shoe peg does not sit against the snail properly. The end result of getting the shoe location wrong is that it takes a couple pumps to move the cylinders expanders out enough for the brakes to work. It was a common enough problem that in October 1970 Land Rover issued a confidential technical service bulletin (No. 1-F-9) to explain the correct assembly to their own service techs.

I got it wrong often enough on my own truck that I documented it so I would get it right on successive brake shoe renewals.

http://www.expeditionlandrover.info/landRoverFAQ/FAQ_rearbrakes.htm

[glbft1]

I can pull the rears apart again... when when i assembled compared shoes to
The ones on the rig and matched up also read your site Terri-Ann,
When I installed these brakes I wound the snails back put on the rotors and adjusted them out very little and the brake stops the wheel, if the drums were to far out would the snail still allow contact but not the wheel cylinder??
If its not the install on the shoes and its not the wheel hubs, possibly a collapsing brake line???
I appreciate everyone's help with this, it is a great learning tool, and I get a up close and personal tour of this series.

[Jeff Aronson]

Greg,

The adjusters can be turned such that they would stop or slow the wheel, but the wheel cylinder pistons will only travel a fixed distance on each pump - and it's not very far. The adjuster can move the shoes a greater "distance" than the pump on the cylinder.

If you lie under the car while someone pumps the brake, you could see if the rear hose is ballooning under pressure. It should not move out when pumped; you might feel a bit of "thump" when you hold the line. I doubt it would collapse because the pressure would move outward.

Have you had the chance to measure the rear drums? When you removed them with the new shoes, did they slide off easily or did it take some yanking? More tellingly, when you put them on, did you have to compress the shoes together and then push the drums over the shoes? My experience with Series brakes is that when the shoes are new and the drums are the right diameter, it's a very tight squeeze to get them on until the shoes have worn down over time. Drums that have been turned too many times will mean the piston has to expand more than once [meaning more than one pedal pump] to effect a proper pedal.

We're all eager to hear what you discover as the cause[s] of this exasperating brake job.

Jeff

[glbft1]

hey jeff,
will call tonite.... I am thinking I will just go ahead and replace the rear drums anyway, that way they are new