so I've got series 3 109 with twin leading brakes at the front one day I noticed that the front brake lines were a bit perished and not serviceable so I decided to change them before all this the brake worked fine and there was a firm pedal however once I changed the brake lines and bled the system I noticed pedal was abit spongy and you had to pump the pedal to get a firm pedal.

Now to fill you in how I bleed the system with eazi bleed kit. I start with rear o/s wheel jack it up turn the brake adjusters till wheel locks up and back it off one serration, then bleed brake I then move onto the n/s wheel. I then clamp of front brake hoses with hose clamps and check brake pedal for firm responsive pedal which I was getting. I then move onto the pretty much done the same jacked one wheel up at a time locked wheel backed off one serration and bled brake. however the still had a spongy pedal just to confirm it weren't the servo I clamped of front and back hoses pedal was solid. so I bled the front again leaving the back clamped this time I clampe of both cylinders with g clamps and bled the brakes the pedal was no different.
hitting a wall I spoke to a fellow landy enthusiast I told him I've checked the brake drums look fine checked the brake shoes some wear nothing drastic , and cylinders looked fine no major leaks.
he did say to me there is a leading edge on each brake shoe check with a Vernier

sorry for the story tried to keep it short anyway suggestions would be great?

Sounds very much like trapped air to me. coincident failures are not unknown, but I wonder if you have entrained air in the fluid as you have topped up the master cylinder?

You are not on your own with tales of difficult to bleed Landie brakes, this subject comes up every few months.
I do not know the answer as I have never failed to bleed and get a "good peddle" I just gravity bleed, that is open the bleed nipple and wait until fluid is running clear. No pumping or buggering about, works for me.

Gravity feeding great when there's two of you when there's one can be abit awkward and Suppose I could of trapped air I mean everything mechanical is working fine I thought that myself seeing a you have to pump the pedal for it to go hard might try purging new fluid through entire front brakes. To be honest I've never had trouble bleeding brakes until now. I have noticed something though the master cylinder seems to be pressurising is this normal I mean literally you have to use water pump pliers to remove cap is that normal.

I gravity bleed if I have time, if not I use a hand vacuum pump at the nipple end,both are one man jobs for me

Master reservoir should not be pressurising.

I had a similar issue with my old 109. I ended up using one of those one man bleed kits that are about £5 from halfords. Flushed the hole system with about two bottles of dot 4 and that seemed to do the trick. If you have changed brake lines i'd check that all the connections are done up correctly and you haven't ruined the threads etc.

Have you checked the master? My clutch master was shot and it kept drawing air into the system.

Was thinking about reverse bleeding anyone had experience doing it that way the principles of fluid dynamics state it would be easier doing it that way. Oh I didn't mention it has been converted to a 300tdi so it has brake vacuum feed on master cylinder could that cause the master cylinder to pressurise

morgan1994 said:

it has brake vacuum feed on master cylinder could that cause the master cylinder to pressurise

Click to expand...

Nope, can't see that see being possible - if it were possible for the vacuum pump to have contact with the fluid side of the master cylinder - it'd suck all the fluid out, not pressurise it. It'd also make quite a mess near the vac pump !!!