'73 Series III rear brakes problem

[1973series3]

After my Rover sits for a couple of days the rear brakes drag pretty heavily.

The shoes are new, the snail adjusters are adjusted all the way to the "loosen" position so they are not over adjusted.

The wheel cylinders do not leak.

And I replaced the rubber line at the rear.

Incidentally,the brake lights stay on like the switch is stuck on.

These could be 2 different problems, but I am not really sure what would be my best move to be to fix this issue.

Hopefully you all can help out.

[SafeAirOne]

I would look for an obstruction in the plumbing or an improperly adjusted or malfunctioning master cylinder. Also, I'd check that all the rear brake shoe springs are on properly. TeriAnn has a good page (or pages) on brakes on her site. Google "TeriAnn Wakeman land rover" if you aren't familiar with the site.

The brake light switch on the SIII is mechanical and it resides on top of the brake servo tower. Easy to get at and see what's going on with it.

Is your brake pedal retracting fully?

[slowmo]

Not sure about the system on a Series 3, but if the master cylinder doesn't release the pressure when the pedal is released, it seems the brakes would remain locked AND the brake light would remain on. Wild a$$ guess but I think a master cylinder kit or replacement is in order.

Of course this would occur during regular driving as well. If that is not the case...are you sure it is the rear brakes and not the transmission brake? Could be the tranny brake needs some attention?

[TravelinLight]

A common problem is the springs being installed incorrectly. Can you post a picture of how you have them set up?

[1973series3]

The springs are installed correctly, I guess I should have thought to type that in my first post. While I was trying to eliminate the more obvious potential causes.

The pedal is in fact retracting fully. And the park brake is perfectly adjusted and brand new.

I too am wondering about the master cylinder, would it be easier to change the entire unit or buy the rebuild and fool with it?

As far as an obstruction in the line...I had wondered about that too, but surely after bleeding the system several times anything in there is out by now I would think.

[Les Parker]

Unless one or more of the brake hoses is failing internally, causing a flapper valve effect.
When were the hoses last replaced?

[1973series3]

I have no way of knowing that. Other than the rubber line at the rear that I replaced recently.

So, do I replace the master cylinder or start pulling rubber lines?

[LaneRover]

Not sure what would cause it to happen. I had one that built up pressure IF I used the brakes a lot. That was a deteriorating brake line.

Is there anyway that this could happen when the booster lost its vacuum over a few days? Almost like there was a tiny hole of sorts that then caused caused the pressure to build up on the 'apply brakes' side of the booster? Don't know if that is even possible but I can't think of much other than gummy shoes that would get worse over a few days.

[slowmo]

The brake lights staying on still makes me think the master cylinder is not releasing the pressure. I would go that route first. Personally, I would replace the cylinder as kits often don't match up 100% with whatever version you have.

[Les Parker]

So, what was the rear hose like that has been replaced?
Was it leaking, or replaced as a matter of course?

[1973series3]

The brake lights staying on still makes me think the master cylinder is not releasing the pressure. I would go that route first. Personally, I would replace the cylinder as kits often don't match up 100% with whatever version you have.

That is what I was thinking too. But being new to these machines and their quirks, I wasn't sure if I was missing anything else.

I had no idea about the kits not matching up, seems like a new one will be the best next move.

[1973series3]

So, what was the rear hose like that has been replaced?
Was it leaking, or replaced as a matter of course?

I read on here that sometimes due to them breaking down they could possibly cause the issue I am having. I didn't seem to help me.

But I DO enjoy getting RN boxes in the mail.

[SafeAirOne]

The brake lights staying on still makes me think the master cylinder is not releasing the pressure.

Though I agree that dragging rear brakes is the result of retained pressure in the hydraulic system, I think the brake light is a red herring. Presuming a foreign (to the SIII) pressure-operated brake light switch hasn't been added to the plumbing, the SIII brake light switch is a mechanical switch. If the brake pedal is fully retracting (and the OP says it is), and the switch isn't broken, and the switch is adjusted properly, the light should go out regardless of any pressure retained in the hydraulic system.

[1973series3]

Okay, I replaced all of the rubber hoses with the braided stainless hoses and anew master cylinder from our host, bled the system etc.

Yesterday, after sitting for maybe 2 months, I fired Maggie up and the rear brakes were fine as I started to back up, but after traveling maybe 6ft, the rear braked locked up HARD. When it does this I usually drive forward a little and it sorta works loose, but when I hit my pedal going forward, it really locked up my brakes.

This event seems to culminate after she has sat for an extended time.

I eventually got it out of the garage and went for a drive.

I must confess, this is really getting me down.

[SafeAirOne]

Is the MC rod adjusted IAW/the FACTORY workshop manual?