Drum brake "diving" problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

shuttermutt · 01-13-2004, 11:54 AM

Hey all! My 68 has drums all the way 'round and the truck has a tendency to "dive" to the passenger side under moderate to heavy braking. Normally, I'd just write it off since nearly every drum brake equipped GM vehicle I've ever driven was the exact same way. However, it seems to be getting a little worse lately. What exactly causes this?

**old Rusty C10** · 01-13-2004, 11:56 AM

is your front end components good and not worn ( springs shocks)

shuttermutt · 01-13-2004, 12:00 PM

Quote:

Originally posted by old Rusty C10
is your front end components good and not worn ( springs shocks)

Everything appears to be okay. The shocks pass the official "Bounce Test" and the ball joints, tie rods, and so forth are good. No, this definately feels like the passenger front wheel is grabbing hard before the driver's front wheel.

Paul72 · 01-13-2004, 12:02 PM

Maybe check the adjustment on the driver's side drum.

**CPNE** · 01-13-2004, 12:07 PM

Usually signifies unequal (higher) pressure to side it pulls toward.

Had 68 burb with EXACT same problem. Replace your wheel cylinders (most likely culprit). While yo have it torn down you might as well replace hoses, shoes, and toss in a Maxi-pack. This will solve your problem.

shuttermutt · 01-13-2004, 12:14 PM

I figured it was an adjustment and/or worn brake part issue. What's a Maxi-pack? I'm pretty sure my truck's a male.

Paul72 · 01-13-2004, 12:15 PM

Quote:

What's a Maxi-pack? I'm pretty sure my truck's a male.

LOL

**CPNE** · 01-13-2004, 12:21 PM

Sorry, that's what the local NAPA calls a kit containing all new springs and retainers for your brake shoes. Sorry, they don't make the style with "wings".

shuttermutt · 01-13-2004, 12:34 PM

Ah... groovy!

gr8scott51 · 01-13-2004, 02:12 PM

If your wheel cylinder is dripping brake fluid on your shoes, they will grab. I know.

*67Fleetsidedream* · 01-13-2004, 03:09 PM

I would bleed the brakes and see if that fixes it. You may have air in the lines. If that doesn't fix it then you will need to replace the brake cylinders on the side that it is not grabbing on.

Rooster's 67 · 01-13-2004, 03:48 PM

just convert it over to disk and be done with it.

shuttermutt · 01-13-2004, 04:14 PM

Quote:

Originally posted by Rooster's 67
just convert it over to disk and be done with it.

Easier said than done, my friend. When it's not 10 below zero, I'm not in the middle of a 1,700 mile move, and I have a garage again, then I'll consider the disc brake conversion.

86SILVERADO · 01-13-2004, 10:10 PM

Mutt,

I hear ya Bro. course it's only in the single digits here. Hope you are headded south!

68 Suburban · 01-13-2004, 10:28 PM

Could be a sign of a week front passenger spring. After 35 years of the engine torquing to that side, it tends to weeken the spring. I bet if you look at a lot of these old trucks, they sit and inch or two lower on the front passenger side.

shuttermutt · 01-13-2004, 10:45 PM

Quote:

Originally posted by 86SILVERADO
I hear ya Bro. course it's only in the single digits here. Hope you are headded south!

Well, no. I'm going a little South, but much more West. From Northern Maine to Minnesota. Woo-hoo!

Rooster's 67 · 01-13-2004, 10:54 PM

i hear ya shuttermutt bout the whole fun situation ya got goin on.

look for grease or brake fluid on the shoes, and possibility of a colapsed hose on the front left is possible too. restricting the fluid flow to the left cylinder.hardware on the brakes can affect it too, so can adjustment.
dont totaly overlook the rears, a pull to one side can be caused by a rear on one side having an issue, but yours sounds like it is in the front.

Longhorn Man · 01-14-2004, 12:14 AM

The first thingi would doo is djust the brake adjuster, and if it does not turn freely, remove the drum and clean up the adjuster and put some antiseize compound on the threads.
Being that it is getting worse, that tells me that his drivers side shoes are not adjusting much, if any, and the wear is making them more and more out.
Try that while keeping an eye open for fluids coming out teh bottom of the drum, and also for crushed brake lines.

68CST327 · 01-14-2004, 12:34 AM

I have the same brake diving problem too. I checked underneath the truck the other day and I'm leaking fluid all over the inside of the right rear tire, so I'm thinking it's probably the wheel cylinder that needs replacement. Also interesting that a problem in the rear can cause the brake drag in the front, but I think that's probably what the problem is on my truck. Thanks to everyone in this thread for the new info.

Blue Beard · 01-14-2004, 12:54 AM

I have the same problem, but haven't found any leaks. New springs, hard brake pedal.........

Longhorn Man · 01-14-2004, 01:02 AM

Quote:

Also interesting that a problem in the rear can cause the brake drag in the front,

Can you explain that? I see no way this can physicly happen...nor have I ever seen it on any old stuff, nor new vehicles.

68CST327 · 01-14-2004, 01:36 AM

Quote:

Originally posted by Longhorn Man

Can you explain that? I see no way this can physicly happen...nor have I ever seen it on any old stuff, nor new vehicles.

I dunno, I read it somewhere in this thread.

Longhorn Man · 01-14-2004, 08:10 AM

OK, I think you misread what was actually ment.
If your left rear brake is dragging, it will pull the truck to the left, much like if it was a front brake. This can actually be misleading when trying to troubleshoot it on a test drive.

68CST327 · 01-14-2004, 01:01 PM

Quote:

Originally posted by Longhorn Man
OK, I think you misread what was actually ment.
If your left rear brake is dragging, it will pull the truck to the left, much like if it was a front brake.

Yeah, I pretty much got that idea when I read it the first time, but somewhere along the line when I typed my response back out, I got things mixed up.

Forgive me, too many long days at work + not enough sleep at night =

I should have typed: "Also interesting that a problem with the brakes in the rear can cause what seems like brake drag in the front."

Jace's68 · 01-14-2004, 05:31 PM

Things to check.

1. Make sure both font brakes are adjusted the same.
2. Check for wheel cylinder leaks.
3. Could also be caused by a bad rubber brake hose. If one side is getting more fluid pressure, it will cause it to pull like you described.
4. One other thing is to make sure that the shoes are installed correctly. The short shoe goes in the front, and the long shoe in the rear. I have seen lots of people get this wrong.

I had the same problem with the 68 I just bought. When I inspected my brakes everything needed to be replaced. After replacing both front hoses, one wheel cylinder and installing a new set of shoes the problem is gone. I hope this helps.

01-13-2004, 11:54 AM	#1
shuttermutt Don't say "Oops!", Doctor Join Date: Nov 2003 Location: Houston, TX Posts: 677	Drum brake "diving" problem Hey all! My 68 has drums all the way 'round and the truck has a tendency to "dive" to the passenger side under moderate to heavy braking. Normally, I'd just write it off since nearly every drum brake equipped GM vehicle I've ever driven was the exact same way. However, it seems to be getting a little worse lately. What exactly causes this? __________________ 'Mutt 1968 CST LWB: R.I.P. 1967 Chevelle: TPI 454 beast 1967 C10 SWB: Claimed when Bumpster didn't put it on his list

01-13-2004, 11:56 AM	#2
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,307	is your front end components good and not worn ( springs shocks) __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

01-13-2004, 12:02 PM	#4
Paul72 Registered User Join Date: Sep 2003 Location: Waterloo, IA Posts: 1,147	Maybe check the adjustment on the driver's side drum. __________________ '72 Chevy K20 - 383/4sp/205 - SOLD after 41 years in the family Next project - K/5 Tahoe (71 Blazer on 99 Tahoe chassis) Build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=789958

01-13-2004, 12:07 PM	#5
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,664	Usually signifies unequal (higher) pressure to side it pulls toward. Had 68 burb with EXACT same problem. Replace your wheel cylinders (most likely culprit). While yo have it torn down you might as well replace hoses, shoes, and toss in a Maxi-pack. This will solve your problem. __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

01-13-2004, 12:14 PM	#6
shuttermutt Don't say "Oops!", Doctor Join Date: Nov 2003 Location: Houston, TX Posts: 677	I figured it was an adjustment and/or worn brake part issue. What's a Maxi-pack? I'm pretty sure my truck's a male. __________________ 'Mutt 1968 CST LWB: R.I.P. 1967 Chevelle: TPI 454 beast 1967 C10 SWB: Claimed when Bumpster didn't put it on his list

01-13-2004, 12:21 PM	#8
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,664	Sorry, that's what the local NAPA calls a kit containing all new springs and retainers for your brake shoes. Sorry, they don't make the style with "wings". __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

01-13-2004, 12:34 PM	#9
shuttermutt Don't say "Oops!", Doctor Join Date: Nov 2003 Location: Houston, TX Posts: 677	Ah... groovy! __________________ 'Mutt 1968 CST LWB: R.I.P. 1967 Chevelle: TPI 454 beast 1967 C10 SWB: Claimed when Bumpster didn't put it on his list

01-13-2004, 02:12 PM	#10
gr8scott51 Registered User Join Date: Mar 2003 Location: Bremerton, WA Posts: 1,839	Look for leaks If your wheel cylinder is dripping brake fluid on your shoes, they will grab. I know. __________________ Silence is golden, duct tape is silver. - Scott

01-13-2004, 03:09 PM	#11
67Fleetsidedream Wiseass secured himself a BAN Join Date: Nov 2000 Location: MOON!!! Posts: 2,282	I would bleed the brakes and see if that fixes it. You may have air in the lines. If that doesn't fix it then you will need to replace the brake cylinders on the side that it is not grabbing on.

01-13-2004, 03:48 PM	#12
Rooster's 67 Registered User Join Date: Sep 2003 Location: DFW Posts: 765	just convert it over to disk and be done with it. __________________ The problem with America is stupidity. I'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself?

01-13-2004, 10:10 PM	#14
86SILVERADO Registered User Join Date: Dec 2002 Location: Hills of Western Mass Posts: 626	Mutt, I hear ya Bro. course it's only in the single digits here. Hope you are headded south! __________________ 86 Silverado C10 back to 305 power! 67 C30 Dually Dump, with 350 transplant, Rockhauler 05 Duramax 3500 "If at first you don't succeed, try a bigger hammer" Member of the 1-Ton club!

01-13-2004, 10:28 PM	#15
68 Suburban Registered User Join Date: Oct 2000 Location: From Chicago, Live in Phoenix, AZ Posts: 6,802	Could be a sign of a week front passenger spring. After 35 years of the engine torquing to that side, it tends to weeken the spring. I bet if you look at a lot of these old trucks, they sit and inch or two lower on the front passenger side.

01-13-2004, 10:54 PM	#17
Rooster's 67 Registered User Join Date: Sep 2003 Location: DFW Posts: 765	i hear ya shuttermutt bout the whole fun situation ya got goin on. look for grease or brake fluid on the shoes, and possibility of a colapsed hose on the front left is possible too. restricting the fluid flow to the left cylinder.hardware on the brakes can affect it too, so can adjustment. dont totaly overlook the rears, a pull to one side can be caused by a rear on one side having an issue, but yours sounds like it is in the front. __________________ The problem with America is stupidity. I'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself?

01-14-2004, 12:14 AM	#18
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	The first thingi would doo is djust the brake adjuster, and if it does not turn freely, remove the drum and clean up the adjuster and put some antiseize compound on the threads. Being that it is getting worse, that tells me that his drivers side shoes are not adjusting much, if any, and the wear is making them more and more out. Try that while keeping an eye open for fluids coming out teh bottom of the drum, and also for crushed brake lines.

01-14-2004, 12:34 AM	#19
68CST327 Registered User Join Date: Aug 2002 Location: USA Posts: 443	I have the same brake diving problem too. I checked underneath the truck the other day and I'm leaking fluid all over the inside of the right rear tire, so I'm thinking it's probably the wheel cylinder that needs replacement. Also interesting that a problem in the rear can cause the brake drag in the front, but I think that's probably what the problem is on my truck. Thanks to everyone in this thread for the new info.



Register or Log In To remove these advertisements.

01-14-2004, 12:54 AM	#20
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,834	I have the same problem, but haven't found any leaks. New springs, hard brake pedal......... __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo

01-14-2004, 08:10 AM	#23
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	OK, I think you misread what was actually ment. If your left rear brake is dragging, it will pull the truck to the left, much like if it was a front brake. This can actually be misleading when trying to troubleshoot it on a test drive.

01-14-2004, 05:31 PM	#25
Jace's68 Registered User Join Date: Sep 2002 Location: Kentucky Posts: 107	Things to check. 1. Make sure both font brakes are adjusted the same. 2. Check for wheel cylinder leaks. 3. Could also be caused by a bad rubber brake hose. If one side is getting more fluid pressure, it will cause it to pull like you described. 4. One other thing is to make sure that the shoes are installed correctly. The short shoe goes in the front, and the long shoe in the rear. I have seen lots of people get this wrong. I had the same problem with the 68 I just bought. When I inspected my brakes everything needed to be replaced. After replacing both front hoses, one wheel cylinder and installing a new set of shoes the problem is gone. I hope this helps.

Register or Log In To remove these advertisements.