Manky Monkey Motors

Hi

I am a new member, so please bare with me.
Just done a VW brake conversion on a Reliant axel.  The problem is I cannot get brake pedal pressure.  I have done everything: back flushed them to bleed them; put new 5/8 master cylinder on; all new brake pipe; plus I bled them the conventional way.
There is no air in the system, or I least I don't think so, so what could the problem be?  Also tried two sets of VW Golf calipers, both have the same result, no brake pedal.
Has anybody got any ideas please, before I get my hammer to it  >:(
Many thanks in advance, Simon.

hi Ek1, not sure what set up you have, but this is just a thought when we did the xj900 project we did the convertion,when it came to bleeding the brakes for the first time we were getting pressure but then we appeared to lose it again in the end after trying to bleed them several times, we noticed the rod we use from the brake pedal to connect to a leaver on to the master cylinder had bent and we had not realised it as it was under the trike out of sight

just try pulling the calipers of the mountings ,pads out or pushed back  but pipe,s/hoses   still attatched and clamp the  pistons right back (big C type welding grips are good for this) then try ,bleeding the system again and see if you get a ,,stiff,, (oo,eer,missis, ;D) pedal then..

it may be youre working against a pocket of air behind the pistons,

i,ve had the same problem many times over the years on car and commercial setups

what master cylinder did you use car or bike. post a photo of the brake set up.if you tried 2 different calipers have you checked the master cylinder

The callipers are mounted nipple at top?

Pedal ratio would be me bet

Hi again  :)

Thanks for all your replies.
Forgot to mention I have tried three master cylinders, two x 3/4 and one x 5/8, early Landrover ones.
The brake pedal ratio is 9:1.  If there is air behind the pistons, how do you get it out?  I've been doing this for about two weeks and must admit I'm pretty fed up. 
I've even tried the easy bleed, that didn't work either.   Is it just a matter of keep trying?
Many thanks to you all again for your input, Simon.

wherabouts in the country are you ek1, ? ?

maybe another manky monkey could take a look  :)

Ek1, to clarify..... 5/8 master cylinder, golf calipers mounted with bleed nipple at the top, all new pipes and hoses?

Sounds like it`s had more transfusions than the nhs perform in a year, so lets assume (yeah i know.....never assume  ::)), that we are free of air.
Pedal ratio of 9:1 will give enough pressure to stop an artic.
Next guess will be master cylinder travel, are you getting full stroke?

I have dreams about a full stroke...................................................I`ll leave quietly...................... ;D ;D ;D ;D

i had similar problems and was told it was because i had operated the handbrake before getting pressure to footbrake. i had to wind the pistons back in on the calipers, do not operate the handbrake, bleed calipers again. only after the footbrake is working should you operate the handbrake. good luck  :)

Its not the leaving part we are worried about , quite the reverse   ..........   ;D 

  ..  Hagar  ..   ;D

Put up pictures of the master cylinder and pedal setup and of the callipers plus the routing of the pipe work.  ;)

Hello EK1, just to put in my pennyworth. I had a similar problem with the last trike. It turned out to be the operation lever ratio. I'll try to explain ....
From the foot brake pedal I used the original rear brake rod connected to a lever so that when I pressed down on the rear brake lever it pulled the bottom of the connecting rod thus pushing the top of the rod and pushing the operating rod of the master cylinder. It wouldn't operate the brakes at all and I was pulling my hair (what little I have left) out. Someone on here, I can't recall who.....sorry, might even have been Tbone, suggested that the ration of the operating lever might be wrong. I made a new one, the top ( above the mounting/pivot point) being around 3 times longer than the bottom part, fitted it and whoopeeee it worked perfectly. A nice easy fix. I'm not suggesting that this is the problem but its worth looking at as Tbone suggested.
Hope that this helps
Regards
K

story of my life  ;D ;D ;D ;D

ek1..I had similar probs bleeding mine...It turned out that I had the calipers round the wrong way,and  the bleed nipple was slightly lower ,altho' it looked OK. I reversed the calipers,and solved it,but not before spending 2 days trying to bleed them ,and also about £30 on fluid! I was also told to 'reverse bleed' by pumping fluid thro' with a large syringe from caliper toward m/cyl,I also tried an easy bleed which didnt work,and also to maybe leave one corner lifted up overnight to allow air to rise to the top of the system.