CSP solid disk conversion on 69 SC Binding calipers

[boyzie]

Hi All

This post may be going over old ground but I've run into an issue with front brakes binding , now have tried fitting the recommended adapters M12x1 x M10x1 from csp but these don't fit the MC , the copper brake lines go directly into the MC M10x1 fittings ,so no residual pressure valves , have rebuilt the calipers (Delco) as the SC was standing for some months , have re bleed , initial test run some 30 miles all ok , went on another run and problem with binding.

Can usually feel the pedal travel decreases so pressure has built up in the MC when they bind, I 'm thinking , and usually the brake lights flicker when this happens(been told )

So to confirm whats been done so far
brand new early MC no pressure valves fitted ,copper pipes direct
New butty's bits pushrod
Rebuilt calipers

Question is where do I go from here to rectify?
Pushrod adjustment?
New MC?

Any help greatly appreciated

Cheers

 

[Moseley]

Start with the easy stuff first, how did you adjust the MC push rod? It is important to have the proper free play on this, otherwise the ports never open up to the reservoir, meaning that natural heat that builds up in the system eventually pressurise the system similar to how you’ve suggested.

If the free play is ok, is the MC definitely retracting back to its rest position?


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[boyzie]

Hi Mosley

Seem to have free play at the pedal of over 10mm, going to get under it now and check the return to rest position , the push rod measurement was taken from either bentley or haynes again going to have a look now , Ill update laters

Cheers

 

[boyzie]

Hi

So checked free play underneath whilst activating the brake arm, have over the 1mm more like 2mm movement before resistance , also lever returns nice and smooth, so marked the push rod and then wound the push rod 1/4 turn to give more movement around 4mm , took for another run , & same problem , binding, and hot rims.

Do I continue winding the push rod in again?

cheers

 

[Moseley]

I haven’t got my Bentley book in front of me, but if you’ve followed that, I’d knock that off the list of potential causes.

Have you removed the residual pressure valves from the MC before fitting? You’ve said you’ve fitted a new one, I’ll be honest, I don’t know if a new MC would come with them fitted or not. I’ve fitted a new one to my drum equipped bus, but to be honest, I’ve no idea if they’re fitted or not! Also, I’ve never looked at one in person, but would expect to see some sort of spring-loaded device screwed into the outlet ports.


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[boyzie]

Hi Mosley

So the old MC didn't have any residual valves fitted same as the new replacement , so Brake lines are direct to the MC , so Residual valves can also be knocked off the list.

So could be a faulty new MC or dodgy flexi / hard line?

Cheers

 

[ozziedog]

My first thought is the ifffy flexi, but not if it’s bothe sides, you’d feel the heat both sides I guess and maybe find the flexi is not too flexibubble if it is just one, but two flex is going at the same time ??? Unless they’re both new and crappy.

Ozziedog,,,,,just some thoughts. :mrgreen:

 

[Moseley]

Hmm, which wheels are you getting the problem on? And are you confirming by feeling the heat coming off the brakes? I'd expect them to be super hot if you're getting the symptoms you're describing!

 

[boyzie]

Hi All

Both sides are super hot , can smell the pads (burnt clutch) , I'm kinda thinking now along the lines of dodgy Brake line or flexi

 

[Moseley]

Both sides front and back?

 

[boyzie]

Just Fronts

 

[Moseley]

I guess it’s feasible that there’s a problem with the lines or flexi’s, but would be very unlucky to have both sides fail at the same time. Is the clearance ok between pads and disc? I’m wondering if they’re not running freely and the drag is building up heat. Do the wheels spin freely off the ground? Is there obvious movement in the pads when pumping the brake pedal?


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[boyzie]

Think I may of found the culprit...

Brake line feeding the fronts from the MC has a kink/dodgy bend , which may be causing the pressure to not be relived after the brakes have been applied and therefore heat is generated which makes the issue worse causing the fluid to expand , so in the process of rectifying this this weekend.

Will report after this weekend

Cheers all for your help , always good to have valid opinions..

 

[Moseley]

Sounds like you've probably found your culprit!