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Pickups Chevrolet S-10 & GMC S15 Sonoma Chevy S10 - GMC S15 and Sonoma Brake Issues
25 messages, Last post on Oct 07, 2009 at 9:42 AM
You are in the Chevrolet S-10 & GMC S15 Sonoma Forum. Your Host is kcram
I have a 1989 S15 pickup. 4.3 V6 auto with 270,000 miles on it. The red brake light has been on now for 2 weeks. I replaced the front pads not the problem. I had to stop real quick the other day. The truck is pulling to drivers side. I don't know if it is the caliper or brake line. Both are oem and has been on the truck from the factory. Also, I have not replaced the back brakes. I am going to check them this week end. The brake fluid is full in the master cyclinder. Don't know why the brake light is staying on.
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Replying to: gearyr (Jun 01, 2007 10:47 am) As I understand it, on my model of truck, the ABS modulator doesn’t stop the front wheels from locking up. It is designed to help equalize the braking energy between the front disk brakes and the rear drum brakes. I guess this is to help maintain stability in hard braking (like when that silver haired lady backs her car out in front of you). However, on most all rigs that I’ve worked on with front disk and rear drum, the front brakes do all the work and the rear brakes are just along for the ride (except provider of parking brake). In my case I started with replacing the pads, then the calipers, then the hoses, then the master cylinder, flushed brake lines, then modulator valve. Off and on I worked on the thing a few days. Back shoes and wheel cylinders were good otherwise I would have replaced them also. When I got done I had some very good brakes and a lightened pocket book. It’s an old truck but I plan on keeping it forever. At least that is what I keep telling my self to justify the ongoing expenditures. Good luck with yours. 
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Replying to: gearyr (Jun 01, 2007 10:47 am) |
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People make the wrong assumption on braking functions. 1] Of course the easy ones are when it's pulling to one side is always 99 out of 100 bad calipers with corrosion on pistons that now won't respond evenly at the same time. 2] Pushing back pistons is the main cause of this damage to start with. As the pads wear, the pistons get more exposed to weather. You make no attempt at cleaning them before pushing them back, and force them past the high pressure o-ring with rust on them. Not Cool. 3] It is true the front disc brakes do most of the work on systems with drum brakes on the rear. 4] The reason front brakes wear out even faster than normal is no one is checking the rear brakes for fit. Here is how the brakes function at the press of pedal. The first half of brake pedal travel is only for the rear brakes. If the rear brakes are out of adjustment, and 99% of the time are, because the auto adjusters never perform the job. If the rear brakes make no contact in the first half of brake pedal travel, the piston in the master cylinder shuts off that circuit and now only applies pressure to the front disc brakes which now are really doing all the work. You want the rear brakes to come on first to set the vehicle up in a straight line of braking before you loose all steering from skidding the front tires. With the rear wheels off the ground and veh in neutral, you should rotate rear wheels and see the braking take place by pulling sideways on emergency brake cable. You can also do this by letting vehicle roll on level surface in neutral at walking pace and apply emergency brake till you feel some braking. This distance you move the lever indicates how far out of adjustment rear brakes are. When you have all 4 wheels stopping you, you will notice increased power of stopping. Here's another sample of test of what the brakes should be. Set the emergency brake to where you just feel it working at rolling walking pace. Back it off one click so the vehicle rolls free. Now do a full on brake pedal test of locking them up at 10 miles an hour. Notice the huge difference? Now go get rear brakes adjusted. One more thing. If you let the rear shoes go too long out of adjustment. They will get out of phase with the fit against the drum. It will take up to 1000 miles and frequent adjustments to get the rear shoes to fit correctly. What happens is the cylinders pushing the shoes out against the drum are now only making partial contact at the top of the arc, leaving the bottom of the shoes never making contact. This shapes the shoes face in a egg shape and now doesn't have full contact to the drum. So if there is plenty of material left on the shoes, then this will work well for you. If the material is worn too far at the top of shoes, then replace them and enjoy instant power at stopping. Rear shoes are generally very cheap and very easy to replace. Warning:::::::::::::: Never -Never use air hose to blow out brake dust from drum brakes. Always use soapy water and a paint brush to wash all parts first before removing them, and catch it all with a paint tray. Process it correctly or you'll end up drinking it in the end. Now after they are washed, then use air to dry off or don't bother. You will now be able to handle parts with out the mess. One other thing. Ever notice how many people complain of shuttering vibration of applying brakes at the front disc's and feel it in the pedal? And steering wheel? Welcome to the over heated Hot Spotted Discs Syndrome. The cast Iron discs can get so hot on panic stops when only the fronts function that it creates hardened swelled spots that now are raised dots on the disc face that bump into the pads, which then transmits this hit against the fluid, and back to the pedal to your foot. These spots are so hard, that the machines used to turn the rotor true also bounce off these spots. Yep, they are now junk. So adjust those rear brakes and you won't have these issues. What's really surprising,,, Seeing New Cars and SUV's still coming out with rear drum brakes. I simply walk away when I look through the rear wheel and see this. I was a potential buyer, but not with 100 year old brake technology. That simply means the rest of the vehicle is not up to my standards. My 98 Isuzu 4x4 V6 Amigo have 4 wheel disc brakes. 2007 brand new RangeRover, the smaller one, Drum Brakes. BMW, and many others would never pull this boner. Pay attention out there.
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Replying to: philscbx (Nov 13, 2007 2:35 am) Ever wonder how they do a emergency 180, rear brakes only. Disc on rear are put on for people like you, if good for the front it must be good for the rear.
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Replying to: gonogo (Nov 13, 2007 9:10 am) 78% of all vehicles on the road still use drum brakes. The information is for those with them to take advantage of 4 wheel brakes vs only 2 wheel brakes. All brake systems regardless of design are made to function with 4 wheel brakes on every car, pickup, etc Now add to the equation, 40 ton semi's. I do these as well, for 35 years. If these brake shoes are not adjusted every week, they get so out of phase that the anti skid will not work. Auto adjusters have advanced further on these than the auto market. You will fail inspection at the drop of a hat if they do not work properly, and maybe make final contact with that object. This isn't rocket science. There is no,,, what you claim as too much rear braking. By default, it's never enough because of wear and no one checking. This is too only make those aware WHY the shit doesn't work properly. Rear braking is all preset at the master cylinder and a floating load sensor that sees how far the rear is loaded down on it's suspension. It's not very smart to discount details that benefit people of what can be confirmed by any brake system engineer. Your welcome to take the entire post to any brake specialist that does high performance braking systems vs Junk Yard Dogs that care less if there were any brakes. Maybe your style of high tech is a stick out the hole in the floor against the tire. Gotta start somewhere I guess. Some started this bare foot. Take 100 cars or trucks with 50,000 miles on them, with drum brakes, and hit the brakes to lock them up at even 30 mph in the dirt. I'll bet you 5g's only the front make a skid mark. That's 2 wheel Brakes Captain, and is the whole point. It might be winded to a point, but 89% of the people on here do not do brake systems as a paying profession. People that have no clue how or why stuff works can't get the information, because they no idea what to look for. Just like you wanting to know about a lobotomy, where would you start? Everyone knows what it's like towing a trailer with brakes vs no brakes. That's the main difference. He who stops first wins. |
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The advantages so out perform 2 disc vs 4 disc. 1] Never have to adjust disc brakes ever. 2] They always work 3] They are self cleaning 4] They are used more and more from Semi's on down, because it's flat out safer, less maintenance, 5] All aircraft use them from the heavies at 450,000 lbs , to small single place. 5] My Sonoma has 4 wheel disc, it's flawless. All high performance machinery has disc brakes. It's Retarded to use drum brakes from 100 year old designs. 6] Drum brakes can get wet and will never even slow you down with both feet on the pedal. That's why people died. That's how insane it is to use them still. 7] The only reason they still use them on the rear is it's base cost is about $10. There is no other reason. 8] You could survey 30,000 brake shops across the US to Holland, and not one person is going to argue the facts about 4 wheel disc brakes vs drum brake combos. 9] If you still disagree in some minor way, go for it. Let's see a You-Tube skid test of one vs the other. 100 w/drum, 100 w/disc. Good luck.. Maybe F1 Racing should go back to drum. Stop at any Motorcycle shop. What's on both wheels? I think the General Public will have a better idea now when they get a little taste of reality. Sorta like someone discovering, and tells you not to eat the Yellow Snow. You end up thanking them in the end, even if you didn't believe him at first.
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Replying to: philscbx (Nov 14, 2007 1:22 am) Have rear disc on my car, pads are half the size and half the thickness, why, they don't want you too swap ends. I will admit they look cool, LOL. |
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| i have a 1993 gmc sonoma brakes are spongy.help! | |
Front passenger brake will not release like it should. It makes the truck drag and the rotor and pads run real hot. Also, when I changed the calipers and pads and bled the brakes, I had low flow out of the bleeder. I have better flow out of the drivers side. Any help would be appreciated. Thanks...
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