Highlighted as a problem where working parts do not return on fully hydraulic Javelin brakes and an added helper spring is advised.
Does this apply to Hydro- Mechanical master cylinder which is of a different design.
Any advice on bleeding Hydro- Mechanical brakes welcome.
Sticking Javelin master cylinder.
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johnairey
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Keith Clements
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Re: Sticking Javelin master cylinder.
The sticking master cylinder which I have had (more than once) may have been due to a wrongly specified seal spreader (https://jowett.net/jowettorg/jowettnet/ ... br-mc2.jpg) which was identified as the cause by Scott Renner and Neil Moore. For many years I have fitted the extra spring attached to the piston extension.
However, my recent investigation showed that this extension slip link may have been worn where it touches the brake pedal arm. Changing it for an un-worn one cured the issue. This was on the Jupiter and I am not convinced that the brake pedal is pulling the piston along its axis. When I free up the big nut at the rear securing it to the chassis to allow the MC to float, the rear of the MC moves about an inch towards the outside of the car when the pedal is fully depressed. https://jowett.net/jowettorg/jowettnet/ ... br-mc3.gif
Although I have set up hydo/mechs I do not think the extra spring is as important as you still will have some brakes if the hydraulics fail.
I just followed the manual for set up which does require some care to get the rear brakes working properly. I had spent a lot of time renovating all the linkages to get rid of any wear. I do not recall bleeding is any different.
However, my recent investigation showed that this extension slip link may have been worn where it touches the brake pedal arm. Changing it for an un-worn one cured the issue. This was on the Jupiter and I am not convinced that the brake pedal is pulling the piston along its axis. When I free up the big nut at the rear securing it to the chassis to allow the MC to float, the rear of the MC moves about an inch towards the outside of the car when the pedal is fully depressed. https://jowett.net/jowettorg/jowettnet/ ... br-mc3.gif
Although I have set up hydo/mechs I do not think the extra spring is as important as you still will have some brakes if the hydraulics fail.
I just followed the manual for set up which does require some care to get the rear brakes working properly. I had spent a lot of time renovating all the linkages to get rid of any wear. I do not recall bleeding is any different.
skype = keithaclements ;
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David Morris
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Re: Sticking Javelin master cylinder.
Hi All,
John asks for advice on bleeding the brakes. In my experience, this is always tricky. Many years ago, I had completely replaced all the components on a full-hydraulic Javelin, and just couldn't get the master cylinder to beed. Working solo in a narrow garage, I then used one of those bleeding kits that use a tyre's pressure to force the fluid around the system. That solved my problem, but I now realise that I should have initially bled the master cylinder on the bench by cracking open the output union, before fitting it.
Watching others bleed classic cars on YouTube from the comfort of my armchair, I notice that when a system is dry, they adopt a simpler method. They bleed the master cylinder on the bench and then just fill the master cylinder reservior and open all the bleed nipples. And then just wait, whilst having a cup of coffee! Gravity does the hard work! Eventually, they see the fluid dripping out of the nipples and nip them up in turn. Then they use an assistant to pump the pedal, as conventually practiced. This usually gets the final bubbles of air out of the system.
Thankfully, my Jowett Generator has mechanical over-run brakes!
Hope this helps and wishing you all a Happy Christmas!
David
John asks for advice on bleeding the brakes. In my experience, this is always tricky. Many years ago, I had completely replaced all the components on a full-hydraulic Javelin, and just couldn't get the master cylinder to beed. Working solo in a narrow garage, I then used one of those bleeding kits that use a tyre's pressure to force the fluid around the system. That solved my problem, but I now realise that I should have initially bled the master cylinder on the bench by cracking open the output union, before fitting it.
Watching others bleed classic cars on YouTube from the comfort of my armchair, I notice that when a system is dry, they adopt a simpler method. They bleed the master cylinder on the bench and then just fill the master cylinder reservior and open all the bleed nipples. And then just wait, whilst having a cup of coffee! Gravity does the hard work! Eventually, they see the fluid dripping out of the nipples and nip them up in turn. Then they use an assistant to pump the pedal, as conventually practiced. This usually gets the final bubbles of air out of the system.
Thankfully, my Jowett Generator has mechanical over-run brakes!
Hope this helps and wishing you all a Happy Christmas!
David
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Forumadmin
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Re: Sticking Javelin master cylinder.
Yes David , good advice. The problem with pumping the brakes prior to the gravity bleed is that the fluid gets full with bubbles which then take extra bleeding to get rid of.
I also fill the MC prior to fitting.
I also fill the MC prior to fitting.