Brake Problems

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william
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Brake Problems

Post by william » Mon Sep 18, 2006 8:48 am

Yesterday while takening the GTE for a drive I noticed a slight drag almost like the emergency brake was slightly pulled. As I continued to drive it was getting worse, luckily was had just passed a friends house and decided to turn around. I powered the car into his drive was and parked. I then borrowed my friends car and headed home to get some tools. When I returned we jacked the front end up and I checked the front wheels, they turned without resistance. I was unable to jack up the rear of the car due to the jack being to short to pump. By this time the car had sat for 20 min. so I thought I would see f I could move it. Sure enough I was able to, so my friend followed me home (about a mile and a half). As I drove, I started smelling very hot brakes. I pulled in my garage and then jacked the rear end up, pulled the rear wheels and noticed a very very hot smokey right rear disk. The left rear was also hot, but as bad. After things cooled down I adjusted both sides of the emergency brake adjustment screws, slapped the wheels back on and went for a short drive. This was to rule out the emergency brake as the problem. Things went pretty well so I continued the drive no sign of resistance, however after about 2 miles I noticed my brake pedal started to feel very heavy almost like pushing a wall. I decided to head home. Once inside my garage I checked the rear calipers, they were warmer then the fronts, but not hot. I'm sure if I would have continued they would have gotten very hot.

So what do think? Master cylinder? hydrovac? Stuck "piston" calipers?

BTW, when I jacked the car up I was able to turn the rear rotors.

Thanks again, As Always.
William
1979 Avanti s/n Rqb-3016
1962 GTE s/n 3447
1960 Alfa Romeo Giulietta Spider 1495*09775

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tyang
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Post by tyang » Mon Sep 18, 2006 4:15 pm

Hi William,

O.K., I'll give it a shot.

The m/c goes to the booster, so if it was acting up, I would believe it would affect all the brakes. The same goes for the booster, as it is connected to all the brakes. I would think that your rear caliper is hanging up. When you jacked the car up at your house, did the rear wheels offer any resistance?

Tom
'63 330 America #5053

william
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Post by william » Mon Sep 18, 2006 4:45 pm

Thanks Tom,

Yes some resistance, but I was still able to move both rotors by hand. I was expecting it to be stuck, so I was susprised both rear rotors moved.

The right rear was the main problem followed by the left. The fronts were not hot and moved freely. I then adjusted the E.brake to take it out of the equation.
William
1979 Avanti s/n Rqb-3016
1962 GTE s/n 3447
1960 Alfa Romeo Giulietta Spider 1495*09775

Rudy van Daalen Wetters
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Post by Rudy van Daalen Wetters » Mon Sep 18, 2006 5:43 pm

William,

I wonder if the brake proportioning valve (located near the radiator) might be acting up? I had this same situation on my Alfa Romeo GTV 2000 on the freeway when the rear brakes literally locked up solid. After sitting a while they worked just fine until they later locked up again after a short period of driving.

Hope this helps.

Rudy van Daalen Wetters
1963 GTE s/n 4001
1966 330 GT s/n 8705

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Yale
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Post by Yale » Mon Sep 18, 2006 8:18 pm

Michael Greenspan should weigh in just about here.
Yale
Ex - 1964 330GT #6097
1963 Abarth Monomille
1970 Porsche 911S
1974 BMW 2002turbo

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tyang
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Post by tyang » Mon Sep 18, 2006 8:24 pm

William,

I wonder if the brake proportioning valve (located near the radiator) might be acting up? I had this same situation on my Alfa Romeo GTV 2000 on the freeway when the rear brakes literally locked up solid. After sitting a while they worked just fine until they later locked up again after a short period of driving.

Hope this helps.

Rudy van Daalen Wetters
Hi Rudy,

I don't believe this is a proportioning valve. It's some kind of pressure equalizer valve, an early form of anti-lock brakes. It is plumbed into the front brakes after the "Tee" that splits the front brakes and rears in my car. I'm not sure if pressure from this unit could affect the rear brakes, but stranger things have happened!

Tom
'63 330 America #5053

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tyang
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Post by tyang » Mon Sep 18, 2006 8:34 pm

Yes some resistance, but I was still able to move both rotors by hand. I was expecting it to be stuck, so I was susprised both rear rotors moved.

The right rear was the main problem followed by the left. The fronts were not hot and moved freely. I then adjusted the E.brake to take it out of the equation.
Hi William,

As mentioned in an earlier post with Michael Greenspan's car, it could be one of the soft hoses retaining pressure to the brakes. With the rear brakes, there is only one on the axle. I may not suspect this, as both brakes would (should)be dragging equally if the flex hose were holding pressure, but then again...

I believe you can unbolt each caliper piston without removing the whole brake assembly from the bracket. You'll have to remove the pads first. With some air pressure, you should be able to pop the pistons out to see if the bores are rusty or dirty. It might just be some trash or rust that hung up the piston.

Tom
'63 330 America #5053

Rudy van Daalen Wetters
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Post by Rudy van Daalen Wetters » Mon Sep 18, 2006 8:39 pm

Hi Tom,

It was my understanding that this valve somehow directs more braking action to the front brakes under heavy braking. My valve was leaking and was rebuilt with a modification to the valve to accept a later kit since the original rebuild seals are long gone. My thought was that since the problem appeared to affect only the rear brakes, that this valve may not be releasing like it should. Perhaps a review of all the calipers, brake pads, master cylinder and this valve would be the best way to go to avoid any surprises down the road.

Rudy van Daalen Wetters
1963 GTE s/n 4001
1966 330 GT s/n 8705

Rudy van Daalen Wetters
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Post by Rudy van Daalen Wetters » Mon Sep 18, 2006 8:43 pm

Jim R. may have some good input on this problem too.

Rudy

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tyang
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Post by tyang » Mon Sep 18, 2006 8:53 pm

Hi Tom,

It was my understanding that this valve somehow directs more braking action to the front brakes under heavy braking. My valve was leaking and was rebuilt with a modification to the valve to accept a later kit since the original rebuild seals are long gone. My thought was that since the problem appeared to affect only the rear brakes, that this valve may not be releasing like it should. Perhaps a review of all the calipers, brake pads, master cylinder and this valve would be the best way to go to avoid any surprises down the road.

Rudy van Daalen Wetters
Hi Rudy,

That the PITA about brakes. The only way to get them to work 100% is to go through the whole system with new parts!

I spoke to Francois once about this strange valve mounted under the radiator, and he explained that it somehow absorbs pressure to the front brakes under hard braking to keep the front calipers from locking up. I'm not sure if I lost some of the explaination in translation, but he continued to say that when this valve is removed, the brakes are NOT affected. Ferrari brakes are balanced front to rear by the size of the caliper bores, so there is no need for a proportioning valve. I know I've heard from at least one GTE owner who had perfect brakes after bypassing this valve.

Tom
'63 330 America #5053

Rudy van Daalen Wetters
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Post by Rudy van Daalen Wetters » Mon Sep 18, 2006 9:05 pm

Hi Tom,

I have heard the same as you. Removing the valve will not change the characteristics as far as balance of front to rear. I kept mine on because I like to keep everything as stock as possible as long it still can function well. I think this might be a good indicator to William to deal with the entire brake system and be done. One temporary fix now may mean disaster later on. I hate surprises when it comes to brakes!

Rudy van Daalen Wetters
1963 GTE s/n 4001
1966 330 GT s/n 8705

Jimmyr
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Post by Jimmyr » Mon Sep 18, 2006 9:35 pm

William, you can eliminate some of the possible causes by checking if pressure is present when the problem happens. If you sense the brakes are dragging, stop and loosen the bleeder on top of the booster and see if pressure is present and if it releases the brakes. If so, it is not a piston hang up, it could possibly be the booster. These early 330 boosters are a Bendix copy and are prone to this type of problem. The P valve under the radiator produces a pressure boost to the front brakes to help prevent early rear wheel lock up. In some Lancias they use it opposite from Ferrari and use it to reduce pressure to the rear brakes. Either way it is not the best item to have in the line, but keeping the system stock is another disscussion. Like Tom has said a complete redo of all brake components is a very smart and safe idea. You can never trust what someone before you has done, especially to something as critical as BRAKES. Go through everything and get it right; this is a good winter project. Jim

whturner
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Brakes Hanging up.

Post by whturner » Mon Sep 18, 2006 9:45 pm

If a brake fails to release long enough to jack up the car, just releasing pressure at the suspect brake with the bleeder valve will tell you a lot. That is the simplest diagnostic, usually.

Cheers
Warren
330 GT Series II sn 10069

airsanford
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Post by airsanford » Tue Sep 19, 2006 12:36 am

I've seen this problem twice over a 25 year period on the same Lusso I work on from time to time, and both times it was the booster.

Lee GTE 2811

racertodd
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Post by racertodd » Tue Sep 19, 2006 12:42 am

I spoke to Francois once about this strange valve mounted under the radiator, and he explained that it somehow absorbs pressure to the front brakes under hard braking to keep the front calipers from locking up.
This valve sounds like a version of a device marketed in the '70's and '80's as the "Safety Braker". It was plumbed into the front brake line and sometimes the rear as well. It is basically an accumulator for brake fluid and its purpose was to dampen pulsations in the brake fluid that occur just before brake lock up. The effect was to make it easier to brake hard without incurring lockup.

They were popular on road racing cars. I saw them alot on autocross cars back in the '80s as well.

Unless you're tracking the car I doubt removing the valve would make much difference in braking.

It is still in productions, now called the Brake-Guard and marketed for RVs: http://www.brakeguard.com

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