I know I know another on disc conversion
?I have 71 disc. brakes on a 68.But they feel like they give,especialy with line lock and after warmed up.

Could I have the wrong master cylinder?Been on there for years now.

I have C.R.S,,,,can't remember sh.. :eek:

could be that master may be going bad
hold foot on brake pedal for one minute and see if it starts dropping
especially when you start noticing this problem
you could also have air in lines or even brake hoses may be getting old
but try master test first

Originally posted by TOM'S 68 CONV:
could be that master may be going bad
hold foot on brake pedal for one minute and see if it starts dropping
especially when you start noticing this problem
you could also have air in lines or even brake hoses may be getting old
but try master test first It is all new or was master cylinder hoses rebleed a few times.Same ol brakes,just not the stopping power I want.

Was thinking with 71 front disc.do I need a dif.MC or prop. valvel?

Disc brakes require a differant MC and a combination valve.On a 71 its mounted on the left frame rail just below the drivers feet.

Originally posted by 71350ss:
Disc brakes require a differant MC and a combination valve.On a 71 its mounted on the left frame rail just below the drivers feet. Thats what I thought got a miss match in there somewhere graemlins/clonk.gif

Dan,
Nice Chevelle,what color blue is that? Are you certain theres no air left in the system?
Did you replace the combination valve when you did the swap? Are you using the 68 drum brake master cyl.
The 71 to 75 combination valve is still available from a number of suppliers,maybe even GM and AC Delco.
Had to look for them, heres the AC delco # 172-1350 and the GM # 1257177 I,m not sure if there current numbers.

Originally posted by 71350ss:
Dan,
Nice Chevelle,what color blue is that? Are you certain theres no air left in the system?
Did you replace the combination valve when you did the swap? Are you using the 68 drum brake master cyl.
The 71 to 75 combination valve is still available from a number of suppliers,maybe even GM and AC Delco.
Had to look for them, heres the AC delco # 172-1350 and the GM # 1257177 I,m not sure if there current numbers. Thanks John, Car is the kk code orginaly was to light, now turcoise metalic 19 year's old,needs some brush ups here and there.Pictures suck non digital camera.

I know the prop. valvel never got changed,needs changed anyway had the wire go bad to it,the one that tells an idiot his brakes are going out graemlins/clonk.gif

Now I need to get out there and get the numbers off M.C. and match um up with yours.Got lotsa time now no job redface.gif

Dan,
Sorry if you misunderstood me,those numbers are for the prop valve.Post the numbers off the MC maybe someone can identify it.