Brakes ( again)
Discussion
Hi all,
Before I seriously just run it at the nearest wall any suggestions as usual :
Front brakes replaced with the Princess "upgrade" and still getting pedal variance and symptoms of air.
Despite about 2 gallons of brake fluid, pressure bleeding , two people bleeding, jamming pedal down overnight etc am still unable to cure the pedal issue.
I have even unbolted Calipers and rotated to try and bleed out any air but still the same pedal issues.
The only thing I have done also is changed the master cylinder and fitted the Steve Heath rear remote bleeder extension gadget.
I have even had the car on a brake machine in a garage and rears are releasing ok and bite power is MOT standard.
Have done 280 miles now and still pants.
Speaking to several mechanics they don't seem to worry about "bench bleeding " the master cylinder which I didn't do .
So real point is WTF ! Could it be air in master cylinder despite all the bleeding carried out or even a " dud " master cylinder or the Steve Heath gadget causing an air trap ? Or something I have seriously overlooked ?
Braveheart
Before I seriously just run it at the nearest wall any suggestions as usual :
Front brakes replaced with the Princess "upgrade" and still getting pedal variance and symptoms of air.
Despite about 2 gallons of brake fluid, pressure bleeding , two people bleeding, jamming pedal down overnight etc am still unable to cure the pedal issue.
I have even unbolted Calipers and rotated to try and bleed out any air but still the same pedal issues.
The only thing I have done also is changed the master cylinder and fitted the Steve Heath rear remote bleeder extension gadget.
I have even had the car on a brake machine in a garage and rears are releasing ok and bite power is MOT standard.
Have done 280 miles now and still pants.
Speaking to several mechanics they don't seem to worry about "bench bleeding " the master cylinder which I didn't do .
So real point is WTF ! Could it be air in master cylinder despite all the bleeding carried out or even a " dud " master cylinder or the Steve Heath gadget causing an air trap ? Or something I have seriously overlooked ?
Braveheart
Seems these calipers are a pain to bleed, don't have them and not speaking from experience.
Only thought I had is that if air can enter the system nothing will help.
Air entering at the master or any of the brake line connections, caliper seals worn?
Feel sorry for you as it seems you have tried all the possibilities
which sort of would have sorted it.
For my putting my wedge on Belgian plates I had to reinstall the original front brakes (non vented in my case) and wasn't happy at all. Yes it would stop the car probably ok for the '80s, but now back on the hispec 300mm 4-pot and it brakes as a sportscar should. Could feel the flexing of the standard hoses, pedal felt like a sponges but wasn't.... etc.
Basically I didn't trust the original setup, all good parts and as good as new, but need to feel confident about my brakes at all times. Perhaps we are 'spoilt' by modern cars and over assistance.
Rob
Only thought I had is that if air can enter the system nothing will help.
Air entering at the master or any of the brake line connections, caliper seals worn?
Feel sorry for you as it seems you have tried all the possibilities
which sort of would have sorted it.For my putting my wedge on Belgian plates I had to reinstall the original front brakes (non vented in my case) and wasn't happy at all. Yes it would stop the car probably ok for the '80s, but now back on the hispec 300mm 4-pot and it brakes as a sportscar should. Could feel the flexing of the standard hoses, pedal felt like a sponges but wasn't.... etc.
Basically I didn't trust the original setup, all good parts and as good as new, but need to feel confident about my brakes at all times. Perhaps we are 'spoilt' by modern cars and over assistance.
Rob
I had the AP 4 pot on the 280i and it made a massive difference..We did spend about four hours bleeding them though when the fluid was changed..Starting from the rear and the lowest nipples first..There were three nipples plus a balance pipe on the AP's..I guess four without the pipe...
I changed my 350i set up from the standard 2 pot with solid discs to the standard 2 pot with a spacer and vented discs and again a big improvement...Admittedly i don't drive as ...."confidently" as i used to...Might be age or the thought of smashing up my P&J....
I changed my 350i set up from the standard 2 pot with solid discs to the standard 2 pot with a spacer and vented discs and again a big improvement...Admittedly i don't drive as ...."confidently" as i used to...Might be age or the thought of smashing up my P&J....
Braveheart,
Just a thought, the original "Princess" fitment had two seperate feeds to the calipers fed from the dual circuit system (IIRC 1 circuit was 2 front and the other circuit as 2 front + 2 rear).
When I upgraded to the Tower View Racing setup years ago there were details of how to modify the spacers to make them single feed. I mounted a "Y piece" on the end of the stainless flexible hose and fed both pairs of pistons seperately leaving the calipers standard.
Since fitting I've bled the brakes a number of times to flush out old fluid and always had a solid brake pedal, it is now possible to lock both front wheels something I found was impossible on the old setup.
Is this why you're having so much "fun" in bleeding the brakes?
Regards,
Brian and a Red 350i
Princess calipers + 300mm disks and now power steering!
Just a thought, the original "Princess" fitment had two seperate feeds to the calipers fed from the dual circuit system (IIRC 1 circuit was 2 front and the other circuit as 2 front + 2 rear).
When I upgraded to the Tower View Racing setup years ago there were details of how to modify the spacers to make them single feed. I mounted a "Y piece" on the end of the stainless flexible hose and fed both pairs of pistons seperately leaving the calipers standard.
Since fitting I've bled the brakes a number of times to flush out old fluid and always had a solid brake pedal, it is now possible to lock both front wheels something I found was impossible on the old setup.
Is this why you're having so much "fun" in bleeding the brakes?
Regards,
Brian and a Red 350i
Princess calipers + 300mm disks and now power steering!
Many thanks all for all your replies.
Zig it is the remote bleeder he did as an aftermarket upgrade ( a piece of flexi that just moves the rear bleeder point to a more accessible position)
The issue over separate feeds is interesting the callipers were modified years ago by Hi Spec in days when Geoff was approachable LOL !
They have been drilled internally and o ringed and the feed is only from the top and one pipe.
I have 4 bleed nipples per side one next to the feed in , one at 90 degrees above that on the side and one either side at 90 degrees in the middle of the piston casting both sides.
Big Red rebuilt them recently so hopefully no issues there.
I still am not sure regarding the bench bleeding bit ( master cylinder ) and to be honest am considering the Hi Spec upgrade when funds allow.
Thanks everyone for your valued advice have ordered a vacuum bleeder to try and reverse bleed through each nipple to see if this helps.
Regards
Braveheart
Zig it is the remote bleeder he did as an aftermarket upgrade ( a piece of flexi that just moves the rear bleeder point to a more accessible position)
The issue over separate feeds is interesting the callipers were modified years ago by Hi Spec in days when Geoff was approachable LOL !
They have been drilled internally and o ringed and the feed is only from the top and one pipe.
I have 4 bleed nipples per side one next to the feed in , one at 90 degrees above that on the side and one either side at 90 degrees in the middle of the piston casting both sides.
Big Red rebuilt them recently so hopefully no issues there.
I still am not sure regarding the bench bleeding bit ( master cylinder ) and to be honest am considering the Hi Spec upgrade when funds allow.
Thanks everyone for your valued advice have ordered a vacuum bleeder to try and reverse bleed through each nipple to see if this helps.
Regards
Braveheart
If you have a pressure bleeder, try setting to a much higher PSI than what it says, maybe 30 not 20, leave it connected for a while and make sure nothing is leaking.
With the vacuum bleeders its very hard to see if there is any bubbles in the system as it will suck air round the nipple thread, so will always look like its got air, when it has not. you can use both systems at the same time just make sure the vacuum system is always under vacuum.
They are a right pain but once right they seem to stay that way.
With the vacuum bleeders its very hard to see if there is any bubbles in the system as it will suck air round the nipple thread, so will always look like its got air, when it has not. you can use both systems at the same time just make sure the vacuum system is always under vacuum.
They are a right pain but once right they seem to stay that way.
braveheart 3 said:
Many thanks Adam,
Going to try again to pressure bleed at a higher pressure and see what that brings first.
Will keep you posted
Regards
Braveheart
If using higher than the recommended pressure (20 psi?) you need to be careful that the fluid does not get forced from the master cylinder reservoir cap and all over the engine bay. Going to try again to pressure bleed at a higher pressure and see what that brings first.
Will keep you posted
Regards
Braveheart
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