60 Veloce two shoe Brake Problems - Page 2

**Britalia** · #16 (**permalink**) 05-30-2008, 07:53 PM

George,
Here is another idea... not sure where this will lead, but maybe it will point you in the right direction. I am not sure if my thought process is correct, but here goes.
Adjust all all six shoes so that they are tight to the drums. At this point you should not be able to turn any of the wheels. Hit the brake pedal once to set the wheel cylinder pistons. Ideally this would then give you the maximum brake pedal height, since you have taken out any shoe clearance. Any remaining slop in the brake pedal should then be in the linkage due to wear, or adjustment. Could there be some wear in your pedal box ? There should be some free play. I think I have about 3/4 inch in my brake pedal. I can measure it if that would help.
All this would assume that you have bled the system completely, which you have. I am assuming that your concern is the low pedal, and not necessarily how hard you have to push. How hard you have to push would be a function of the bore size of the master cylinder and the bore size of the wheel cylinders and the coefficient of friction between the drum and the lining. When you push on the brake pedal, the master cylinder displaces enough fluid to move six wheel cylinder pistons until the lining material contacts the drum.
I am no expert on this stuff, just trying to help. I am sure there are better ideas and explanations.

Chuck

Gordon Raymond · #17 (**permalink**) 05-30-2008, 07:53 PM

One inch would be correct for two shoe front drums, to the best of my knowledge.
Hope some of these ideas help!

Gordon Raymond · #18 (**permalink**) 05-30-2008, 08:00 PM

Humm, I posted, but it didn't take! George, to the best of my knowledge 1" is correct for the two shoe fronts.

alfabits · #19 (**permalink**) 05-30-2008, 08:12 PM

Quote:

Originally Posted by Britalia

George,
Here is another idea... not sure where this will lead, but maybe it will point you in the right direction. I am not sure if my thought process is correct, but here goes.
Adjust all all six shoes so that they are tight to the drums. At this point you should not be able to turn any of the wheels. Hit the brake pedal once to set the wheel cylinder pistons. Ideally this would then give you the maximum brake pedal height, since you have taken out any shoe clearance. Any remaining slop in the brake pedal should then be in the linkage due to wear, or adjustment. Could there be some wear in your pedal box ? There should be some free play. I think I have about 3/4 inch in my brake pedal. I can measure it if that would help.
All this would assume that you have bled the system completely, which you have. I am assuming that your concern is the low pedal, and not necessarily how hard you have to push. How hard you have to push would be a function of the bore size of the master cylinder and the bore size of the wheel cylinders and the coefficient of friction between the drum and the lining. When you push on the brake pedal, the master cylinder displaces enough fluid to move six wheel cylinder pistons until the lining material contacts the drum.
I am no expert on this stuff, just trying to help. I am sure there are better ideas and explanations.

Chuck

__________________
One inch would be correct for two shoe front drums, to the best of my knowledge.
Hope some of these ideas help!
__________________
Gordon Raymond
Illinois SNO Chapter DIRECTOR
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**Britalia** · #20 (**permalink**) 05-31-2008, 03:55 AM

Sorry George,
Never mind... I guess interpreted your problem as being low pedal. Your problem would then seem to be a lack of hydraulic pressure at the wheel cylinders, or inadequate coefficient of friction between the linings and the drums.
FYI ... I had my shoes lined by Rochester Clutch and Brake in Rochester NY. They use a woven material that I think they refer to as Kevlar. I am perfectly happy with them, although I think they are a big aggressive in wearing away the drum surface.
It is a shame that you can't enjoy driving such a lovely car. I hope you figure it out soon.
Chuck

alfabits · #21 (**permalink**) 05-31-2008, 10:14 AM

Quote:

Originally Posted by Britalia

Sorry George,
Never mind... I guess interpreted your problem as being low pedal. Your problem would then seem to be a lack of hydraulic pressure at the wheel cylinders, or inadequate coefficient of friction between the linings and the drums.
FYI ... I had my shoes lined by Rochester Clutch and Brake in Rochester NY. They use a woven material that I think they refer to as Kevlar. I am perfectly happy with them, although I think they are a big aggressive in wearing away the drum surface.
It is a shame that you can't enjoy driving such a lovely car. I hope you figure it out soon.
Chuck

Gordon Raymond · #22 (**permalink**) 05-31-2008, 11:13 AM

George,
A thought. IF the linings are dusting, and other front linings exhibited the same hard dead pedal, it's probably time to put in a different, not necessarily new, master cylinder, to see what happens. This is an unpleasant job, due to the tight confines, but should you have a bum MC, the solution should be obvious!

alfazagato · #23 (**permalink**) 06-01-2008, 02:42 PM

I have mentioned this before on the BB but have you ensured that the rear brake cylinders have movement when the brakes are applied. The cylinder moves within the slot in the back plate and is partially pulled back by the springs after use. One correspondent mentioned applying the handbrake to see if this improved matters and effectively removes the problem. Did you try this as a solution?
I have used Alfastop's Mintex linings in the past and they are first-class. Might be the way forward.

alfabits · #24 (**permalink**) 06-01-2008, 06:33 PM

Quote:

Originally Posted by alfazagato

I have mentioned this before on the BB but have you ensured that the rear brake cylinders have movement when the brakes are applied. The cylinder moves within the slot in the back plate and is partially pulled back by the springs after use. One correspondent mentioned applying the handbrake to see if this improved matters and effectively removes the problem. Did you try this as a solution?
I have used Alfastop's Mintex linings in the past and they are first-class. Might be the way forward.

phila3885 · #25 (**permalink**) 06-06-2008, 08:42 PM

I agree the simplest way to proceed is to try new shoes on either the front or rear before you tear the whole system apart. Are you getting any more braking by standing on the pedal? If not, maybe something is interfering with the full stroke of the pedal/master cylinder? Also, I think only some sort of blockage in a line could reduce pressure to one set of wheels, but I don't know how that could happen. I believe that the pressure is always the same at each wheel in a single cylinder system, but the front wheels do most of the braking due to the weight distribution and the "dive" effect. Just some ideas. Good luck.

alfazagato · #26 (**permalink**) 06-07-2008, 12:49 AM

This may be totally silly, but have you cleaned the shoes and inner drum with a brake cleaner before assembly? Have you well chamfered the front and rear edges of the shoes. Did you remember to turn the adjuster snails in the right direction? All problems I have had!

**AlfaDuc** · #27 (**permalink**) 06-07-2008, 07:29 AM

Quote:

Originally Posted by alfazagato

This may be totally silly, but have you cleaned the shoes and inner drum with a brake cleaner before assembly? Have you well chamfered the front and rear edges of the shoes. Did you remember to turn the adjuster snails in the right direction? All problems I have had!

alfabits · #28 (**permalink**) 06-07-2008, 06:17 PM

Quote:

Originally Posted by phila3885

I agree the simplest way to proceed is to try new shoes on either the front or rear before you tear the whole system apart. Are you getting any more braking by standing on the pedal? If not, maybe something is interfering with the full stroke of the pedal/master cylinder? Also, I think only some sort of blockage in a line could reduce pressure to one set of wheels, but I don't know how that could happen. I believe that the pressure is always the same at each wheel in a single cylinder system, but the front wheels do most of the braking due to the weight distribution and the "dive" effect. Just some ideas. Good luck.

redblk63 · #29 (**permalink**) 06-12-2008, 09:27 PM

I do not understand the suggestion of loosening the rear brakes so that "only the fronts are used to stop" and vice versa. Of course, our Giuliettas use a single circuit so that equal pressure is applied to all 6 wheel cylinders. If the rears are adjusted loose, there is just a lower pedal level at which all brakes are applied.

As far as jacking the car up to see if they all are applied, what happened to the old foolproof test of standing on the brakes on a dirt/gravel surface, skidding to a halt, and checking for 4 sets of skid marks? This has helped me find bad (corroded) wheel cylinders more than once. You already mentioned the wear pattern on all four wheels, so this seems unlikely.

I'm thinking you may have to push harder.

Mine also has a pretty long pedal stroke until applied, and like you I just got used to it. No adjustment of the shoe angle seems to make it better.

Let us know how it comes out.

Good luck,
Larry in Pasadena

**pathung** · #30 (**permalink**) 06-12-2008, 09:46 PM

Larry's "dirt-road panic stop" methodology is quite worth a try, IMO.