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#1 |
Registered User
Join Date: Mar 2022
Location: Central Coast CA
Posts: 4
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1969 gmc
Just purchased this truck
![]() This is my first vehicle with drum brakes all around. Is it normal for it to take 4-5 car lengths to slow down? I am also a shorter guy so would like to know if its possible to make the clutch a shorter distance (instead if having to press it down to the floor board) to fully disengage the clutch?
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1969 GMC Camper Special 4x4 1972 K5 Blazer 1972 Chevelle |
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#2 |
Special Order
![]() ![]() Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,859
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Re: 1969 gmc
Welcome to the board! Nice looking GMC. Is it an 8-lug 4wd (K2500)? It's hard to reply to what you are describing, but you will definitely notice the brakes don't grab like disc brakes. What do you mean by slow down? Slow down at all or slow down significantly? I've always driven these trucks, both drum and disc, and used to not even notice a difference. I'm sure there is a decent difference, but I never paid much attention to it. I haven't had one with drum brakes for a very long time. I guess it matters all the more these days with other vehicles able to stop much shorter than years past, as well as the knucklehead way people drive ahead of their thoughts these days. You really need to be on your toes.
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#3 |
Registered User
Join Date: Apr 2011
Location: Ridgeley WV
Posts: 229
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Re: 1969 gmc
The only difference I could ever tell was between power and manual. And even with disk the manual brakes sucked.
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#4 | ||
Registered User
Join Date: Mar 2022
Location: Central Coast CA
Posts: 4
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Re: 1969 gmc
Quote:
Quote:
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1969 GMC Camper Special 4x4 1972 K5 Blazer 1972 Chevelle |
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#5 |
Registered User
Join Date: Apr 2011
Location: Ridgeley WV
Posts: 229
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Re: 1969 gmc
new wheel cyl and hardware kits are reasonable.
If I don't know when they were last serviced I just replace it all. Shoes can actually harden up and be less effective. Don't scrimp on safety. Its to late after an accident to say "maybe I should have repaced that". |
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#6 |
Post Whore
![]() Join Date: Feb 2016
Location: Portland Oregon
Posts: 11,117
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Re: 1969 gmc
I would pull each drum off and inspect the brakes. You may have more than one issue.
Look for anything broken or bent, uneven wear on the shoes, oil on the shoes, glazed drums, grooved drums, drums that are exceeded the stated wear diameter or rusted drums. You should be able to move the slave cylinder pistons into the cylinder slightly by prying with a screwdriver to check for a frozen piston. It may be that new shoes and having the drums turned followed by a proper bedding in of the new shoes may solve your issue.
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Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
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#7 |
Registered User
Join Date: Apr 2012
Location: Falls Church Va
Posts: 77
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Re: 1969 gmc
Having all four drums properly adjusted is really important. You want it so that they drag just a little when the wheels are turning.
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#8 |
Registered User
Join Date: Jun 2016
Location: Bremerton, WA
Posts: 171
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Re: 1969 gmc
All 4 drum brakes should have close to the same stopping distance as disc/drums. The big difference between disc and drums is the amount of pedal force required and an increased stopping distance when the drums are wet or very hot (long steep grades). If everything is working correctly, you should not see a decrease in stopping ability in normal conditions.
What commonly happens is old cars that have been sitting awhile with moisture in the brake fluid and both pistons of each wheel cylinder are not moving (one gets frozen) so only one brake shoe is moving and not both. Pretty soon the one shoe starts to wear very quickly and there isn't enough travel left in the linkage to take up for the worn brake shoe. Or the drums have been turned too many times and there isn't enough travel in the brake linkage to engage the drums when the shoes are half worn.
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1969 Custom Camper C20; Factree Air, 350/TH400/Dana 70U with C30 wheel cylinders, Disk brakes, H4 conversion, headlight relay mod, 3G 135 amp alternator. 7500 GVW |
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#9 |
Special Order
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Location: Mt Airy, MD
Posts: 85,859
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Re: 1969 gmc
When I rebuilt the '70 C/30 I used for my business I never considered converting to discs like you see people do today. I located all new parts and rebuilt the whole system. This was a 157" wheelbase truck with an 11' service body with 15' ladder racks, always loaded up, too. That thing stopped just fine. I went all out because I was building a daily work truck rather than buy new. You could get the same results without going to that extent. Drum brakes are very serviceable.
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#10 |
Registered User
Join Date: Mar 2022
Location: Central Coast CA
Posts: 4
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Re: 1969 gmc
Thank you to everyone! I ordered all new wheel cylinders and brake pads..hopefully I can get those in working order soon... Also has anyone seen this before? It isn't a twin stick since the lever to the left of the gears is not attached to the transfer case.. The lever is attached to something in front of the sm465..
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1969 GMC Camper Special 4x4 1972 K5 Blazer 1972 Chevelle |
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#11 |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,396
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Re: 1969 gmc
Need pics, but maybe a PTO lever?
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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