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debejoman

New Member
Hi , I have replaced all the original wheel cylinders with new, as per the 1952 set up , I've also replaced the pipe work with !/4" pipe, I want to replace the original master cylinder with a series 2 two bolt fixing cylinder using a conversion kit, I have a problem !! starting with a good solid pedal then for no explicable reason when driving I loose all pressure.
Also I have put an inline servo under the seat, should I use a 86" cylinder or could I use the larger capacity 109" unit ?
 
debejoman said:
Hi , I have replaced all the original wheel cylinders with new, as per the 1952 set up , I've also replaced the pipe work with !/4" pipe, I want to replace the original master cylinder with a series 2 two bolt fixing cylinder using a conversion kit, I have a problem !! starting with a good solid pedal then for no explicable reason when driving I loose all pressure.
Also I have put an inline servo under the seat, should I use a 86" cylinder or could I use the larger capacity 109" unit ?
Click to expand...
Doing all that will have introduced a massive amount of air into the system, so you will probably need several goes at bleeding, with rest periods in between. I find with Series brakes a simple gravity bleed works best, no pedal pumping.
Unless you have replaced the brake shoes as well, you are going to need to adjust all the snail cams as per the manual as well.

What sort of inline servo have you used?
 
Turboman said:
Doing all that will have introduced a massive amount of air into the system, so you will probably need several goes at bleeding, with rest periods in between. I find with Series brakes a simple gravity bleed works best, no pedal pumping.
Unless you have replaced the brake shoes as well, you are going to need to adjust all the snail cams as per the manual as well.

What sort of inline servo have you used?
Click to expand...
Hi yes all new shoes, and the servo is new off EBay with 3/16 pipe threads I have done a similar brake referb in the past but then I used 3/16 th pipe all around with smaller - later wheel cylinders . I wondered if the existing master cylinder was letting fluid run back ?
 
debejoman said:
Hi yes all new shoes, and the servo is new off EBay with 3/16 pipe threads I have done a similar brake referb in the past but then I used 3/16 th pipe all around with smaller - later wheel cylinders . I wondered if the existing master cylinder was letting fluid run back ?
Click to expand...
I meant what make is the servo?

I doubt if the increased pipe size is going to make much difference, to be honest, but I have always found the inline servos to be quite troublesome to bleed.
 
Turboman said:
I meant what make is the servo?

I doubt if the incresed pipe size is going to make much difference, to be honest, but I have always found the inline servos to be quite troublesome to bleed.
Click to expand...
Ok cheers I will have a go at bleeding the out pipe at the servo, I don’t know the manufacturer but I will see what numbers/ I’d might be on it.
 
debejoman said:
Ok cheers I will have a go at bleeding the out pipe at the servo, I don’t know the manufacturer but I will see what numbers/ I’d might be on it.
Click to expand...
I think the original inline servos on Series were made by a firm called Clayton Dewandre. I very much doubt if they are still around, but those servos had a bleed nipple on the body of the servo itself.
If you don't get a result after several attempts, I would try removing the servo and running a brake pipe direct to the brakes, if you get a good pedal then, the servo is your problem.
 
Turboman said:
I think the original inline servos on Series were made by a firm called Clayton Dewandre. I very much doubt if they are still around, but those servos had a bleed nipple on the body of the servo itself.
If you don't get a result after several attempts, I would try removing the servo and running a brake pipe direct to the brakes, if you get a good pedal then, the servo is your problem.
Click to expand...
Ok thanks, do you think that hid I were to change the master cylinder that using a 106” would cause any issues?
 
debejoman said:
Series 1 long wheel base 106 inches with slightly bigger Bore master cylinder than the 86”
Click to expand...
OK. I thought they were 107 or 109 inch. but no matter.

On Series 2s, and very likely Series ones as well, there were two types of master cylinder, CV and CB types.
From memory alone, the CVs were used on 88" vehicles, the CB on 109" and six cylinder models.
So it would make sense to use a CB type if you are fitting a servo.

But as I don't know how this translates into the world of Series Ones, I am going to tag @Remora107 , as he is likely to know.
 
Turboman said:
OK. I thought they were 107 or 109 inch. but no matter.

On Series 2s, and very likely Series ones as well, there were two types of master cylinder, CV and CB types.
From memory alone, the CVs were used on 88" vehicles, the CB on 109" and six cylinder models.
So it would make sense to use a CB type if you are fitting a servo.

But as I don't know how this translates into the world of Series Ones, I am going to tag @Remora107 , as he is likely to know.
Click to expand...
Cheers my mistake 109 not 106, I thought a CB might do the trick but I will have a day trying to bleed the system first. Thanks for your advice.
 
If it's not too late I would advise not using a CB master cylinder ( the one with the large hex plug at its rear end). The CB master cylinder has what's called a residual pressure valve built into it, behind that hex plug. It's designed to keep a small amount of line pressure in the brakes when the pedal is not pressed but for your Landy fitted with a servo, it could prevent the servo shuttle valve from returning to its "off" position when you take your foot off the pedal. I have also found that the CB gives a more spongey feel to the brake pedal compared to the CV and they can be more awkward to bleed too.
Using a CV master cylinder will let the servo return any fluid back to the reservoir and hence let the servo retract to its off position.
 
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