The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 04-08-2010, 09:37 AM   #1
C10_86
Registered User
 
C10_86's Avatar
 
Join Date: Feb 2010
Location: Morgan, MN
Posts: 19
Replaced brakes, truck still hops while braking

My truck was starting hop/bounce pretty bad at about 35 mph while braking. I did new cylinders and shoes in the rear and new rotors and pads in the front and it still does it just not as bad. Anybody know what else can cause this?

Chad
C10_86 is offline   Reply With Quote
Old 04-08-2010, 09:46 AM   #2
68Timber
I know the pieces fit
 
68Timber's Avatar
 
Join Date: Nov 2007
Location: MONTGOMERY, AL
Posts: 5,523
Re: Replaced brakes, truck still hops while braking

That's not a brake problem, that's worn shocks that do that. Replace your shocks.
__________________
John

79 2wd Blazer (Bruiser)
85 M1009 Blazer (Sarge) build
74 Honda Z50 build
68Timber is offline   Reply With Quote
Old 04-08-2010, 10:05 AM   #3
C10_86
Registered User
 
C10_86's Avatar
 
Join Date: Feb 2010
Location: Morgan, MN
Posts: 19
Re: Replaced brakes, truck still hops while braking

Thanks John,

That was my next thought. Brakes were due to be replaced anyway.
C10_86 is offline   Reply With Quote
Old 04-08-2010, 10:46 AM   #4
N2TRUX
Happy to be here
 
N2TRUX's Avatar
 
Join Date: Mar 2000
Location: Cypress, TX
Posts: 39,023
Re: Replaced brakes, truck still hops while braking

Chad I think John is spot on. It sounds like weak shocks to me.
__________________
Follow me on Facebook and Instagram @N2trux.com

Articles-

"Jake" the 84 to 74 crewcab

"Elwood" the77_Remix

85 GMC Sierra "Scarlett"

"Refining Sierra"
N2TRUX is offline   Reply With Quote
Old 04-08-2010, 12:46 PM   #5
tommie
97' Tahoe 2dr/2wd
 
tommie's Avatar
 
Join Date: Jul 2002
Location: Huffman,TX
Posts: 1,168
Re: Replaced brakes, truck still hops while braking

did you machine the drums? what about the rotors?

sounds like a warped drum to me..
tommie is offline   Reply With Quote
Old 04-08-2010, 01:06 PM   #6
C10_86
Registered User
 
C10_86's Avatar
 
Join Date: Feb 2010
Location: Morgan, MN
Posts: 19
Re: Replaced brakes, truck still hops while braking

Rotors are new, tried to turn old ones but they ended up too thin. Drums were machined. I am going to get new shocks. They have definately been on the truck a long time.
C10_86 is offline   Reply With Quote
Old 04-08-2010, 03:58 PM   #7
tommie
97' Tahoe 2dr/2wd
 
tommie's Avatar
 
Join Date: Jul 2002
Location: Huffman,TX
Posts: 1,168
Re: Replaced brakes, truck still hops while braking

do you only feel the vibration/ hop when applying the brakes?
tommie is offline   Reply With Quote
Old 04-08-2010, 04:37 PM   #8
C10_86
Registered User
 
C10_86's Avatar
 
Join Date: Feb 2010
Location: Morgan, MN
Posts: 19
Re: Replaced brakes, truck still hops while braking

Yes and it is only the front end that starts to bounce a little at about 35 mph and it goes away at 25 mph. It is much better with new brakes but still there.
C10_86 is offline   Reply With Quote
Old 04-08-2010, 08:36 PM   #9
tommie
97' Tahoe 2dr/2wd
 
tommie's Avatar
 
Join Date: Jul 2002
Location: Huffman,TX
Posts: 1,168
Re: Replaced brakes, truck still hops while braking

are you sure that the new front rotors you installed are not warped? I have had new front rotors that were dropped during shipping, and warped.....

can you feel the vibration in the steering wheel when applying the brakes?
tommie is offline   Reply With Quote
Old 04-08-2010, 08:43 PM   #10
Kalashnikov46
Registered User
 
Kalashnikov46's Avatar
 
Join Date: Mar 2010
Location: Casper, Wyoming
Posts: 147
Re: Replaced brakes, truck still hops while braking

mines got really bad to. no vibration in the column or pedal, its the whole truck thats doing it, and it bounces bad on roads that appear smooth like im on a wavy ocean. lol. new shocks came in today from LMC (their HD 20 dollar ones), ill put them on tomorrow before leaving for the Denver auto show. hopefully this fixes mine. ill let you know.
Kalashnikov46 is offline   Reply With Quote
Old 04-08-2010, 09:12 PM   #11
billnorman
Registered User
 
Join Date: Mar 2009
Location: glen burnie md
Posts: 174
Re: Replaced brakes, truck still hops while braking

On a smooth dry roadway where nobody else is around, keep one hand on the emergency brake RELEASE and at about 35, depress the emergency brake, while holding the release in the release position. If the truck "bounces" it's a warped rear drum or grease on one or more. If it slows smoothly, your rear brakes are probably OK. If it still surges when stopping normally, it may be a warped or dirty rotor. It has been said if the lug bolts are not evenly torqued, it can warp drums or rotors. Are your tires (very) old?
billnorman is offline   Reply With Quote
Old 04-08-2010, 09:14 PM   #12
C10_86
Registered User
 
C10_86's Avatar
 
Join Date: Feb 2010
Location: Morgan, MN
Posts: 19
Re: Replaced brakes, truck still hops while braking

No vibration in column or pedal. it just starts to bounce at 35mph while braking. Goes away at 25-30mph. And if I press the pedal a little harder when it starts the bounce it will come out of it quicker than normal. I guess it could be possible that the new rotors are slightly warped.
C10_86 is offline   Reply With Quote
Old 04-08-2010, 09:54 PM   #13
tommie
97' Tahoe 2dr/2wd
 
tommie's Avatar
 
Join Date: Jul 2002
Location: Huffman,TX
Posts: 1,168
Re: Replaced brakes, truck still hops while braking

normally, if the rotors are warped, you will feel it in the steering wheel, if the rear drums are warped, you will feel it in the body.

I would replace the rear drums, since you said they were already out of spec....
tommie is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 05:19 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com