Bleeding the bleeding brakes!

ScratchyDom said:

I don't see how it can really effect bleeding. I'll post photos inside the drums when they're apart next.

In the meantime, here's my Dorset axle stand. (I'd used all three of mine and didn't fancy going underneath to sort the flexi with the Landy up on a trolley jack only).

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Well as I saw it, if the shows were hooked together at the top instead of just one side to the post, the slave cylinder would be pulled in all the way as opposed to just one piston being pulled in.
The master cylinder will only displace enough fluid to push half the cylinder out on 4 drums, instead of having to extend all 4 slave cylinders the full capacity,
So leaving the pedal with the illusion of it nôt being bled, where as infact it is

Ah yeah it's often the best way mate,I generally change as axle sets, you can clamp of the others then bleed that will let you isolate the problem. Loving the axle stand

Nowt like flaring your own flanges!

What a nightmare your having. I feel your pain aswell, took my landy for not only its first drive after all my work but to bed the brakes and mot. Failed on the soft brake pedal... suprise suprise! I havent clamped off the flexi's yet but done a liter of brake fluid so far as it dies feel like air as it pumps up. I have compleate new brake setup. All Bar the drums.... what a joy..... look forward to hearing the results of your new parts and good luck!!!

Thanks for the encouragement. I've been away for a week (was supposed to be snowboarding but went to Bulgaria so it was slushboarding and getting quite pished on Bulgarian beer) going to give them a go tomorrow, I hope.

So I clamped my pipes off the other day. Its air in the rear brakes/lines. So I have made newpipes and will try them monday and let you know what I find. Im thinking its holdimg air in the rear top cylinders. So going to do the same as I do on jaguar xk's and similar. Pull the shoes off and pistons out, use a end of cable tie to push past the seal. Burp the air out. Msy not work but worth a try.

Just an update of my progress.... bled the brakes by the bleed nipple on the rears, the fronts were clamped off. Still spongy pedal, so bled fron the pipe into the wheel cylinder and from the t peice union. Pedal still long but a bit better. Im guessing now the pedal is long due to theshoes not bedded to thr drums. And there is nothing adjus t ing the shoes so they are returning back to the stop every time. Next I will plumb in a valve to hold a small amount of pressure on the rears to hopfully solve my problem....maybe...

davidlampard said:

Just an update of my progress.... bled the brakes by the bleed nipple on the rears, the fronts were clamped off. Still spongy pedal, so bled fron the pipe into the wheel cylinder and from the t peice union. Pedal still long but a bit better. Im guessing now the pedal is long due to theshoes not bedded to thr drums. And there is nothing adjus t ing the shoes so they are returning back to the stop every time. Next I will plumb in a valve to hold a small amount of pressure on the rears to hopfully solve my problem....maybe...

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I don't understand, what do you mean there is nothing adjusting the shoes?

Apart from the cylinders pushing the shoes out there is nothing to take up the slack (apart from manual adjuster) so the springs pull the shoes all the way back. Im thinking the first pump of the pedal moves the shoes out to meet or close to meeting the drum s, the second is a good pedal as they dont have to move as far....
I might be wrong.....

From what I hear the 109's are renowned for been an absolute **** to bleed the brakes. I found this out just after I had replaced mine a few years ago.After reading various tricks and tips on tinternet and months of trying to get them right I gave in and took them to brake specialist, left the car there for the day only to be told when I went to collect it that none of his staff where old enough to what drum brakes are!!!!. Phoned up Halfrauds ( getting desperate ) as they did a price menu which included changing brake fluid. Ah ha brain working overtime gave them a call to check it was for ANY car. Yes came the reply, and the guy on the phone actually sounded promising. Had chat with him for about 5 mins booked it in, result. Only for him to say " oh, as long as it isn't one of those big old landrovers because we did one last week and never want see another" They charged the bloke buy the hour and it cost him a few hundred £££. according to halfraud man. Good luck, hope you get a result.

davidlampard said:

Apart from the cylinders pushing the shoes out there is nothing to take up the slack (apart from manual adjuster) so the springs pull the shoes all the way back. Im thinking the first pump of the pedal moves the shoes out to meet or close to meeting the drum s, the second is a good pedal as they dont have to move as far....
I might be wrong.....

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The snail adjusters hold the shoes in position just shy of the drum. You'll never get good pedal with too much movement on the shoes no matter how much you bled

Well, I've now replaced the master cylinder, all the wheel cylinders, front shoes and drums, all the flexi lines and quite a lot of the copper pipe. Bled twice this afternoon and *still* no frickin' pedal. Takes several pumps for the pedal to come up rather that the two that I had before. I reckon there's still air in the system and will have another go tomorrow.

May have been mentioned before but have you reversed the connections on the front brakes [that is feed to lower cyl and bleed on the top] helps a lot with bleeding also are snail cams good [have known some replacement snails to be to small] This might sound silly are all the back plates the right one's each side, I once bought a 109 that pulled right when going forward and left in reverse, in the end found it had two left hand back plates on the front!!!

Don't understand how you'd get feed into the lower cylinder on the front, surely the flexi ain't long enough... Cams are all good, bought replacements but didn't fit them as the existing ones are fine. Backplates seem right enough...

You have to fix flexi to bracket and run copper to the lower cyl and back to top cyl, makes it much easy'r to get all the air out.

Anyone had any break throughs yet? My next idea is to fit a inline valve to the rear brakes. To hold a small amount of pressure in the rears. Might sort it out...... worth a try...

I'm trying the slowly slowly method of gravity bleeding. Got the back jacked up high and level, the NSR rear has been open for about half an hour, I'm going to another half hour then do the OSR etc.

I wouldn't go as far as fitting valves, that seems a bit daft to me...

I cant see how air can still be in the system...... bleed nipples are at the top of cylinders. Where can it be sitting....?

davidlampard said:

I cant see how air can still be in the system...... bleed nipples are at the top of cylinders. Where can it be sitting....?

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As standard the bleed nipples are on the lower cyl's on a 109,hence the mod suggested in previous post.

I had this problem many years ago when I fitted 6 cyl front brakes to my 109 for a V8 conversion.

I ended up supporting the front axle on stands and removing the brake backplates/drums complete from the axle, I then hang them upside down under the inner wings and used 3 of those rubber automatic bleeding tubes one on each brake bleed nipple front and back at once (collect the fluid in pop bottles if possible or wrap front brake assemblies in clingfilm to protect them). Pumped about 2 litres of fluid through the system. Perfect brakes no trapped air.....

Refit the brake plates to axles...

Sorted

hth