Brake issues, back here again

Found the mis-behavin plug wire and got that corrected so, of course, off for a ride......

Well let me start this at the beginning. A few weeks ago when I was doing numerous small things to the vette I took some slack out of the emergency brake cable. Drove her and felt like the rear brakes were dragging particulary as I drove on. Came home with slightly smoky rear brakes and backed off the emergency brake cable thinking I had taken a bit too much slack up.

Today following the plug wire correction I took her out for a drive again. Same thing. Seems to feel like it comes a little more from L rear but both L and R heat up too much. I'm thinking it's the old "I need SS sleeved rear calipers" gig.

Pads all around are new condition and the smell, I believe, was brake as opposed to other common smells but before I invest in two new SS sleeved calipers I'd like some input.

Thanks,

Ken

:ack2: :ack2: :ack2: :ack2: :ack2:

Are you sure that the E-Brake cable is releasing completely?
I had a truck that didn't and I had the same scenario.

No I'm not sure

What diagnostic steps can I take to make that determination?:thumbsup:

I found this out when I replace very badly worn out brake shoes. The drum would not go back on. The cable was rusted just enough that it kept the E-Brake mechanism engaged.

Do you have disk or drum on the rear?

Just went out....

And backed off the adjustment nut and made sure the cables were loose.

What you say makes sense. Before I adjusted the cable I had taken the car on two runs of maybe 130 and 150 miles without any problem. After adjustment, problems.

Logically both calipers should not mal-function at the same time with or without Murphy's involvement.

I'll take her back out tomorrow evening and see how she acts.

Thanks bro,

Ken

OOPS

all disc's

Good luck! :thumbsup:

Me...

I'd block the front wheels, lift up the rear end and spin the rear tires, listening for any type of Dragging. if that didn't convince me... I'd start the car up, put'er in gear and have momma steppin' on the accelerator while i'm behind the car looking at the rear end with a flash light (if need be) looking for smoke etc.:shrug01:

~Ray

Good solid diagnostic approach, I like it doctor. I just can't believe that both rear calipers would begin binding without me being the cause :banghead: I'll work on that Saturday, runnin kinda hard till then.

Thanks, I appreciate it.

Ken

I attached a picture of how the emergancy brake system is comprised on your car from the GM parts catalog. As you can see you have two little brake shoes that fit inside the rotor hub. The hub acts like a brake drum. More than likely when you adjusted the cables the shoes moved tightly against the drum. Now this type of emergency brake system is famous for the shoes freezing in place and the backing plate and springs and hardware getting rusty, thats why most people don't use the emergency brake because they freeze. Now if the shoes are expanded you might have a problem getting the rotor off because the little brake drum usually forms a ridge on the edge and when the shoes are expanded it can become quite a pain to get the rotor off. If memory serves me correct there is a special tool to get at the adjuster to adjust the shoes. Heat is the biggest enemy of any brake system. If you heated up the little drums enough to smoke there is a possibility that the hubs got real hot and damaged either the shoes the rotors or both. You can jack the car up and try to spin the wheels by hand and see if they are dragging. I would seriously doubt you need new calipers, however SS sleeved calipers are the way to go, but remember you will need to turn your old calipers in for cores so they must be rebuildable, they are very valuable. I'd change all 4 if your going to do it and convert to DOT 5 silicone brake fluid, but thats just me. Muskeegon Brake has great deals on r/b calipers if you buy a set of 4, lifetime guarentee if I remember and free pads. Just my .02

While your in there you and have the car jacked up you might want to check your rear wheel bearings for play. It would be a shame if they heated up and snapped off the spindle and the wheel went thru the quarter panel.

how can i get my hands on a similiar catalog? (c5)

ClockworkC5 said:

how can i get my hands on a similiar catalog? (c5)

Click to expand...

You can't. Paper catalogs have been out of print for at least 12 or 15 years. C5 GM parts catalogs are only available in microfich or electronic parts catalog form. The catalog I have covers 53-82 and it was published in December of 83.

Nytro said:

You can't. Paper catalogs have been out of print for at least 12 or 15 years. C5 GM parts catalogs are only available in microfich or electronic parts catalog form. The catalog I have covers 58-82 and it was published in December of 83.

Click to expand...

Nytro, nice to see you back. It's been awhile! :wavey:

Gonna be a busy Saturday

Gonna do all the inspections and tests you all suggest. Just hoping that I just pissed her off and didn't cause any damage. I'll know Sat.

:toetap05:

2Vettes said:

Nytro, nice to see you back. It's been awhile! :wavey:

Click to expand...

Ditto :wavey: :crazy03:

Just finished a diaognostic exploritory

Blocked her up, put her in neutral and spun the rear tires. Felt a bit of binding that I didn't like. crawlled under her and found that I had trapped one side of the emergency brake cable under a seat bolt (I had to use slightly longer bolts because I added heat/sound deadening) and sure as s**t I had a line with tension trapped. OK so de-trapped the line and they seem to spin freely.

I'll take her out later and see how she acts.

I knew I picked the wrong career.

Ken

:crazy03: :crazy03:

Up date

Did the longer test drive. As long as I don't use my brakes they do not heat up and drag. Sounds strange I know but the out bound trip I used them normally and they eventually began dragging. Let the cool for 30 or so and drove her home using all gears except for that final touch to stop and she was fine, little or no drag.

Makes me wonder if in the power brake system their is any adjustment possible to components. I'm wondering if the tolerances are just way too close or if as Nitro said the rear emergency brakes are now constantly dragging a bit because I abused them earlier?

Noticed all four corners were pretty farkin warm.

I know the calipers are all self adjusting and the pads appear virtually new.

The new (NOS) power brake system is said to be the same as Chevy installed in 72.

Glad to get some input guys.

Ken

I really don't think your going to be sure of anything until you take the rear rotors off and do a visual of the emergency shoes and the rotors. When you converted to power brakes did they recommend changing the proportioning valve ? Calipers don't adjust like drum brakes do. The pistons, just naturally due to gravity and the fact each piston has a spring behind it keeping outward pressure, will extend as far as possible until something stops them, when the pad hits the rotor. If a piston is cocked or pitted sometimes it becomes stuck in the caliper and when the pedal is stepped on and released it doesen't release properly thus causing a drag. Usually when this happens you will feel a pull when you step on the brake. Care must be taken when you remove a caliper from the rotor as the pistons will push outward until the dust boot stops it. They make special clips that you insert into the caliper before removal to prevent this. I use to just wire tie the pads to the caliper before removal to prevent this.

The rear brake and suspension system on your car is very unique, but the technology is 40 plus years old. As I said before if your rear brakes were smoking something got REAL HOT. More than likely it was the emergency brake shoes. You need to remove the wheels, take off the calipers and rotors and inspect the shoes for wear and cracking, check the drums for hot spots, you'll know cause they will look kinda blue. (As I said before if the shoes are extended rotor removal will be a hassle as the rotor will not just slip off at that point.) You need to check the hardware, the little brake return springs as they could have become fatigued from heat and take apart the adjusters at the bottom of the shoes and grease them to make sure they spin freely and adjust. Once you do all this put em back together, adjust the shoes until they just start to drag and you should be all set. If you have never done a brake job on drum brakes perhaps you should have someone who has experience do it as you don't want brake failure as you have a pretty big investment going there.

I also mentioned about checking the rear wheel bearings for play. You should make sure you do this. What happens is the rear wheel bearings wear at an angle. The pressure from the tire being on the ground now changes and causes the bearing to heat up where it rides on the spindle. Eventually it gets so hot the spindle snaps in half, the car drops to the ground and the wheel goes thru the top of the fender and the car comes to a grinding hault riding on the trailing arm. It's very easy to check. Get the wheel off the ground, place your right hand on the tire at 6 o'clock, fingers on the tread, your left hand at 12:00 o'clock, fingers on the tread, and then gently try to rock the tire. Do the same at 3 and 9. The tire shouldn't move or rock at all. If it does you might have bearing issues that need to be addressed.

If you check the cables to make sure they move freely, inspect, clean and adjust the emergency brake shoes and make sure their operation is functional, check all the involved components for wear and tear and assemble all the parts correctly you will eliminate immensly the chance for a failure and insure yourself that all is functioning as intended and eliminate them as the source of your problem.

Brakes

OK I like it.

First, no, the new brake package said nothing related to the proportioning valve at all, but then again it also came without the first farkin instruction at all. Of positive note was that it was an all inclusive package including every nut bolt and clamp and their was no new proportioning valve.

I did, as you suggested, check the wheel bearings by the method you recommended on Friday when I was checking for drag. seemed nice and tight. I'll check them once again as I get into the rear brakes.

Over the years I have done several brake jobs so this shouldn't be that difficult from what you say as long as few hidden glitches don't pop up.

Thanks for taking the time and helping

Ken :thumbsup:

Thats good news about the wheel bearings Ken as they can be quite expensive to replace.

Good luck with the brakes and remember before you remove the calipers secure the pads to them so the pistons don't push out too far. Check out Ecklers to see what I'm talking about as far as the tool and the clips.

Go to Ecklers.com type in 1972 for the year and then under the search type in brake tools

When I had problems getting the rotors off the emergency shoes in the past, I would use a rubber mallet to get the rotor off the shoes alternating sides while whacking it. Then once I could start to see the shoes I would use a big screwdriver to pry the rotor off the shoes also alternating sides. Naturally I would try to adjust the star wheel in first. Good luck and keep us posted.