brake fluid change - The 1947 - Present Chevrolet & GMC Truck Message Board Network

SkeksisNV · 07-18-2011, 10:41 PM

Today I decided to bleed the brakes. Its been a little squishy since I bought the truck a few months back. As I started on the rear passenger side, the fluid came out a dark, rusty or muddy brown color and seemed very watery vs oily as I swirled it around in the jar. I imagine in the trucks 40 years of existence, the fluid hasn't been changed.

What is the best way to change the brake fluid? Should I stay with Dot-3 or go with Dot-4. From what I understand, Dot-5 is silicon based and shouldn't be used. What brand fluid do you guys recommend? Is there anything else in the brake system that I should check while the fluid is drained?

Thanks for the help.

**lolife99** · 07-19-2011, 08:06 AM

How is the rest of your brake system?
I would look at all the hoses before you decide to change fluid.
I would think DOT-3 or DOT-4 would be fine.

Here's a good article:
(I know it's a BMW,... but there's some goo info here)
http://www.dvatp.com/bmw/diy/brake_fluid_flush/

Also look at this:
http://www.workhorse.com/Portals/0/W...luid%20wip.pdf

SkeksisNV · 07-19-2011, 05:43 PM

Those are good articles. So I emptied out the reservoirs and wiped em clean with a paper towel and filled em with some DOT-3. I then started at the rear passenger side and bled them until the fluid ran clear with no air and did the same on rear-driver/front-pass/front-driver. The brakes seems to work a little better but I am still running into a issue I think.

The pedal will go about 3/4 way down before anything, then it feels like it wants to brake hard. Any idea what this could be? The front brakes I replaced along with calipers and rotor. Rear probably needs a total overhaul. I haven't been brave enough to pull em off and check yet.

cparman · 07-19-2011, 08:42 PM

Please go back to the basics. Pull all four wheels and inspect the brakes, clean and adjust all four wheels ( rears if you have front discs) THEN, bleed the system. A low pedal can be from brakes out of adjustment, or something wrong inside the master cylinder. I am a big fan of replacing the brake fluid in our old trucks. Brake fluid is hydroscopic SP. Meaning that it will absorb water, hence the rusty/mud that first came out of your bleeders.

henri_auzinet · 02-01-2014, 08:56 AM

Its good to change the fluid periodically to avoid corrosion in the brake system.

Tx Firefighter · 02-01-2014, 07:08 PM

New hoses are a good idea. You can get them for 10 bucks each or thereabouts. The'ye rubber and they're 40 years old. Think of the safety aspect. I swap them right away on every truck that I do.

07-18-2011, 10:41 PM	#1
SkeksisNV Registered User Join Date: Mar 2011 Location: Reno, NV Posts: 223	brake fluid change Today I decided to bleed the brakes. Its been a little squishy since I bought the truck a few months back. As I started on the rear passenger side, the fluid came out a dark, rusty or muddy brown color and seemed very watery vs oily as I swirled it around in the jar. I imagine in the trucks 40 years of existence, the fluid hasn't been changed. What is the best way to change the brake fluid? Should I stay with Dot-3 or go with Dot-4. From what I understand, Dot-5 is silicon based and shouldn't be used. What brand fluid do you guys recommend? Is there anything else in the brake system that I should check while the fluid is drained? Thanks for the help. __________________ Gary '71 3/4 ton pickup, 350cid - TH350 I know just enough to get me in trouble

07-19-2011, 08:06 AM	#2
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	Re: brake fluid change How is the rest of your brake system? I would look at all the hoses before you decide to change fluid. I would think DOT-3 or DOT-4 would be fine. Here's a good article: (I know it's a BMW,... but there's some goo info here) http://www.dvatp.com/bmw/diy/brake_fluid_flush/ Also look at this: http://www.workhorse.com/Portals/0/W...luid%20wip.pdf __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

07-19-2011, 05:43 PM	#3
SkeksisNV Registered User Join Date: Mar 2011 Location: Reno, NV Posts: 223	Re: brake fluid change Those are good articles. So I emptied out the reservoirs and wiped em clean with a paper towel and filled em with some DOT-3. I then started at the rear passenger side and bled them until the fluid ran clear with no air and did the same on rear-driver/front-pass/front-driver. The brakes seems to work a little better but I am still running into a issue I think. The pedal will go about 3/4 way down before anything, then it feels like it wants to brake hard. Any idea what this could be? The front brakes I replaced along with calipers and rotor. Rear probably needs a total overhaul. I haven't been brave enough to pull em off and check yet. __________________ Gary '71 3/4 ton pickup, 350cid - TH350 I know just enough to get me in trouble

07-19-2011, 08:42 PM	#4
cparman sharp as a marble Join Date: Jan 2007 Location: atlantic beach,florida Posts: 1,082	Re: brake fluid change Please go back to the basics. Pull all four wheels and inspect the brakes, clean and adjust all four wheels ( rears if you have front discs) THEN, bleed the system. A low pedal can be from brakes out of adjustment, or something wrong inside the master cylinder. I am a big fan of replacing the brake fluid in our old trucks. Brake fluid is hydroscopic SP. Meaning that it will absorb water, hence the rusty/mud that first came out of your bleeders.

02-01-2014, 08:56 AM	#5
henri_auzinet Registered User Join Date: Jan 2014 Location: Florida Posts: 9	Re: brake fluid change Its good to change the fluid periodically to avoid corrosion in the brake system. __________________ I am an immigrant from France and love my '87 Chevy Truck. Sorry English not so good. I want to make friend and write here.

02-01-2014, 07:08 PM	#6
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Re: brake fluid change New hoses are a good idea. You can get them for 10 bucks each or thereabouts. The'ye rubber and they're 40 years old. Think of the safety aspect. I swap them right away on every truck that I do. __________________ I'm on the Instagram- @Gearhead_Kevin



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