Woah! Nelly! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ckhd · 06-05-2002, 10:15 AM

OK, the Suburban's name isn't "Nelly", but yelling "WOAH!" would have done more to stop me than my brakes!

A little history:
I bought this 'burb about a month ago. The guy I bought it from said there was a problem with the brakes. He told me he had done the following: New master cylinder X 2, new brake booster X 2, "professional" did the four corners, new vacuum check valve, and none of it took care of the problem.

Here's what happened... I was headed into town this morning, and just as I was getting in to town, a dumb dog ran out in front of me. I tried a 'panic stop' to avoid the mutt, but I might as well not even hit the brakes. I was able to swerve to miss the dog, but don't know what happened to the brakes. The pedal was hard as a rock, and barely provided any slowing. I was practically standing on the pedal.

Normally, the brakes work great. I'm used to non-power brakes, and so I brake way ahead of time, and usually use gentle, steady pressure, or gentle pumps. When I jabbed them to try to miss the dog, there just weren't any brakes. 100 yard later, doing my normal stop, the brakes worked just fine.

Anyone know why it would do this? What isn't right?

I'm just glad that I wasn't trying to avoid a car, I wouldn't have been able to miss it...

PushinPebbles · 06-05-2002, 10:20 AM

The way my brakes are I would be having dog for supper
The check ball in the master cylinder could have froze up---but you siad it was new Jack

Pont · 06-05-2002, 11:05 AM

I've got the same problem on my 67 4x4, only this generally happens after making a hard left hand turn. Right turns have no affect on the problem. As I'm leaving my favorite fast food Mexican restaurant, exiting the drive-thru making a left turn, my peddle drops twice as far as normal then gets hard but has no stopping power. I haven't replaced master cylinder or booster but have bled the brakes. I thought it might have something to do with changing the front axle over to disc (originally drum brakes up front) but I had this problem before I switched to disc. Doesn't happen all the time but usually when I really need to stop, it won't. Maybe it's a vacuum problem in my case (sitting in the drive-thru at an idle). Not sure, still haven't figured it out.

I think I had seen where someone posted that 67's didn't actually have a proportioning valve, instead it has a distribution block. Am I needing to get an actuall prop valve? When the brakes are working, they seem to work fine.

Sorry ckhd, wasn't looking to take attention away from your post, just thought it was a good time to throw it in to see if someone might have any ideas.

DennyB · 06-05-2002, 11:13 AM

eek: I would check the rubber lines. These can look fine on the outside and be nearly closed on the inside (sometimes due to moisture).
Its possible that breaking hard puts more pressure on the restriction quickly causing it to block the passage where, light pressure allows a small amout of fluid to flow.
Also check the metal lines for kinks or crushed areas.
If you find this is the problem, I would replace ALL the lines.
Anyway, just something else to check.
Denny:

Pont · 06-05-2002, 11:27 AM

Good advice DennyB, I've replaced all rubber lines with extended SS braided lines when I did the lift on my truck. I have checked metal lines also for kinks, looks fine. Only other thing I can think of is a metal line that runs close to the exhaust on the drivers side frame rail. Could this be getting the brake fluid to hot and causing it to boil? Maybe I'm reaching for ideas now!

barn9 · 06-05-2002, 11:57 AM

I'm by no means an expert on brakes, but I think I would concentrate on the mechanical end of the system. Master cylinder and a quart of brake fluid costs less than $20.00, and even a small dog could do much more damage than that, let alone what could happen in any kind of wreck. Good brakes are the most important thing on any vehichle, and taking chances with faulty brakes is just asking for trouble. Hope you guys find your problem before someone gets hurt. And we damned sure don't want any good ol' chevy trucks tore up!

PushinPebbles · 06-05-2002, 05:38 PM

My brakes went out when my dad was driving---to make a long story short--- the metal line that is 94 in lon to the rear axle had a hole in it 3 in away from the rear as far as the rubber hoses up front go i replaced them $16.95 a pop
Jack

HYPERMAN · 06-06-2002, 06:24 AM

Pont, I think I know the problem with your 4x4 on your left turns. I had it on my 70 SWB which was converted to disc.

What was happening to mine was when I turned hard to the left, the hub actually pushed the back of the caliper against the axle pushing the piston back into itself.

When you put the pedal down, the fluid has to push the pistion back to touching the disc, giveing you no real brake pressure.

Take a look at the stop adjusting screw and I'll bet it does not stop your turn until after it hits the caliper.

At least thats what was happening on mine.

Hope this helps.

Peter

Pont · 06-06-2002, 06:37 AM

HYPERMAN, I never thought to look at that. I will check it out and see if that's the case. Sounds logical to me. However, I had the same left turn problem with the old closed knuckle drum brake front axle as well. Thanks, I hope that's all it is..........

06-05-2002, 10:15 AM	#1
ckhd Registered User Join Date: Oct 2000 Location: St. Johns, Arizona Posts: 2,660	Woah! Nelly! OK, the Suburban's name isn't "Nelly", but yelling "WOAH!" would have done more to stop me than my brakes! A little history: I bought this 'burb about a month ago. The guy I bought it from said there was a problem with the brakes. He told me he had done the following: New master cylinder X 2, new brake booster X 2, "professional" did the four corners, new vacuum check valve, and none of it took care of the problem. Here's what happened... I was headed into town this morning, and just as I was getting in to town, a dumb dog ran out in front of me. I tried a 'panic stop' to avoid the mutt, but I might as well not even hit the brakes. I was able to swerve to miss the dog, but don't know what happened to the brakes. The pedal was hard as a rock, and barely provided any slowing. I was practically standing on the pedal. Normally, the brakes work great. I'm used to non-power brakes, and so I brake way ahead of time, and usually use gentle, steady pressure, or gentle pumps. When I jabbed them to try to miss the dog, there just weren't any brakes. 100 yard later, doing my normal stop, the brakes worked just fine. Anyone know why it would do this? What isn't right? I'm just glad that I wasn't trying to avoid a car, I wouldn't have been able to miss it... __________________ my 2¢ - t.i.o.l.i. Bowen 1968 K20 fleet 1969 K10 swb fleet 1972 K10 Suburban 1972 C10 lwb step 1992 K1500 'burb 1995 K2500 'burb 1997 C1500 'burb 1999 K1500 2000 K1500 'burb Why do I own so many Suburbans?

06-05-2002, 10:20 AM	#2
PushinPebbles My dad's 68 Join Date: May 2002 Location: VA Posts: 444	The way my brakes are I would be having dog for supper The check ball in the master cylinder could have froze up---but you siad it was new Jack __________________ Jack M. 67 C-10 SWB 355 built T-350 tranny hurst shifter 17x8in KMC's on michelins, clear tails and back up lights slammedUPDATE i have decided on my bag setup and will post further info when i recieve all the parts **************************** 88 1/2 ton suburban 4x4 350/700R-4having a 9 in lift w/ 38 in tires 4 12 inch Lightning Audios *************************** 87 silverado 3/4ton jacked up 10-12 inches black and rubberized bed coating 35 in michelans ************************** Dad's truck 68 C-10 stepside, 468 BB, tubbed, weld wheels, Nason black,lots more **************************** grand dads truck 68 C-10 stepside fuel inj. 350/700R-4soon in audi silver **************************** 84 toyota pickup 22R 5 speed 2WD slammed, shaved and all the body lines filled w/ buickGN scoop,bout to be sprayed in 2003 mustang green metallic w/ silver flames **************************** S/N=BIGGYTYME@aol.com (hydros) "No fat chics, truck will scrape"

06-05-2002, 11:05 AM	#3
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	I've got the same problem on my 67 4x4, only this generally happens after making a hard left hand turn. Right turns have no affect on the problem. As I'm leaving my favorite fast food Mexican restaurant, exiting the drive-thru making a left turn, my peddle drops twice as far as normal then gets hard but has no stopping power. I haven't replaced master cylinder or booster but have bled the brakes. I thought it might have something to do with changing the front axle over to disc (originally drum brakes up front) but I had this problem before I switched to disc. Doesn't happen all the time but usually when I really need to stop, it won't. Maybe it's a vacuum problem in my case (sitting in the drive-thru at an idle). Not sure, still haven't figured it out. I think I had seen where someone posted that 67's didn't actually have a proportioning valve, instead it has a distribution block. Am I needing to get an actuall prop valve? When the brakes are working, they seem to work fine. Sorry ckhd, wasn't looking to take attention away from your post, just thought it was a good time to throw it in to see if someone might have any ideas. __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness" Last edited by Pont; 06-05-2002 at 11:07 AM.

06-05-2002, 11:13 AM	#4
DennyB Led Sled! Discs R 4 ME! Join Date: Jan 2001 Location: Toms River, NJ, USA (Transplanted Hoosier) Posts: 7,327	eek: I would check the rubber lines. These can look fine on the outside and be nearly closed on the inside (sometimes due to moisture). Its possible that breaking hard puts more pressure on the restriction quickly causing it to block the passage where, light pressure allows a small amout of fluid to flow. Also check the metal lines for kinks or crushed areas. If you find this is the problem, I would replace ALL the lines. Anyway, just something else to check. Denny: __________________ "Never ride faster than your Angel can fly" I.M.O.M,W,J&C Patriot Guard Rider

06-05-2002, 11:27 AM	#5
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	Good advice DennyB, I've replaced all rubber lines with extended SS braided lines when I did the lift on my truck. I have checked metal lines also for kinks, looks fine. Only other thing I can think of is a metal line that runs close to the exhaust on the drivers side frame rail. Could this be getting the brake fluid to hot and causing it to boil? Maybe I'm reaching for ideas now! __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness"

06-05-2002, 11:57 AM	#6
barn9 Half a bubble off! Join Date: Jun 2000 Location: Winfield, Ks, USA Posts: 5,588	I'm by no means an expert on brakes, but I think I would concentrate on the mechanical end of the system. Master cylinder and a quart of brake fluid costs less than $20.00, and even a small dog could do much more damage than that, let alone what could happen in any kind of wreck. Good brakes are the most important thing on any vehichle, and taking chances with faulty brakes is just asking for trouble. Hope you guys find your problem before someone gets hurt. And we damned sure don't want any good ol' chevy trucks tore up! __________________ Just call me LB. '71 Cheyenne, 402BB, hauls blondes, brunettes, or redheads.

06-05-2002, 05:38 PM	#7
PushinPebbles My dad's 68 Join Date: May 2002 Location: VA Posts: 444	My brakes went out when my dad was driving---to make a long story short--- the metal line that is 94 in lon to the rear axle had a hole in it 3 in away from the rear as far as the rubber hoses up front go i replaced them $16.95 a pop Jack __________________ Jack M. 67 C-10 SWB 355 built T-350 tranny hurst shifter 17x8in KMC's on michelins, clear tails and back up lights slammedUPDATE i have decided on my bag setup and will post further info when i recieve all the parts **************************** 88 1/2 ton suburban 4x4 350/700R-4having a 9 in lift w/ 38 in tires 4 12 inch Lightning Audios *************************** 87 silverado 3/4ton jacked up 10-12 inches black and rubberized bed coating 35 in michelans ************************** Dad's truck 68 C-10 stepside, 468 BB, tubbed, weld wheels, Nason black,lots more **************************** grand dads truck 68 C-10 stepside fuel inj. 350/700R-4soon in audi silver **************************** 84 toyota pickup 22R 5 speed 2WD slammed, shaved and all the body lines filled w/ buickGN scoop,bout to be sprayed in 2003 mustang green metallic w/ silver flames **************************** S/N=BIGGYTYME@aol.com (hydros) "No fat chics, truck will scrape"

06-06-2002, 06:24 AM	#8
HYPERMAN Registered User Join Date: Mar 2000 Location: Moncton, New Brunswick Posts: 239	PONT - NO PEDAL AFTER LEFT TURN Pont, I think I know the problem with your 4x4 on your left turns. I had it on my 70 SWB which was converted to disc. What was happening to mine was when I turned hard to the left, the hub actually pushed the back of the caliper against the axle pushing the piston back into itself. When you put the pedal down, the fluid has to push the pistion back to touching the disc, giveing you no real brake pressure. Take a look at the stop adjusting screw and I'll bet it does not stop your turn until after it hits the caliper. At least thats what was happening on mine. Hope this helps. Peter

06-06-2002, 06:37 AM	#9
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	HYPERMAN, I never thought to look at that. I will check it out and see if that's the case. Sounds logical to me. However, I had the same left turn problem with the old closed knuckle drum brake front axle as well. Thanks, I hope that's all it is.......... __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness" Last edited by Pont; 06-07-2002 at 12:54 AM.

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