Author Topic: Soft brakes -- Fluid level, bleeding, and shoes (drum, pb)  (Read 1505 times)

67L48

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Soft brakes -- Fluid level, bleeding, and shoes (drum, pb)
« on: June 24, 2016, 11:24:23 PM »
1967 Camaro, power drum brakes, power steering, powerglide. All stock, so nothing's getting upgraded.

I've had the car since 1989 and can't remember if the brakes have ever been done.  51,000 original miles, so I wouldn't expect that the shoes are bad, but not sure.  I know the wheels haven't been off since the 1990s.

The brakes have been getting steadily softer and I'm hearing squealing when cold.  At this point, I have to brake really hard to stop from highway speeds (55 mph) and I'm not even sure if it's possible to lock up the wheels.  That, to me, suggests shoes are worn.  But, the low mileage makes me think it could be something else.

The brake reservoir on the front of the power assist booster is about 50-75% full.  Tricky part is that this reservoir is angled ... so, as the car sits level, the reservoir tilts back. The rubber/plastic gasket on the lid was convex ... the rubber was poking down into the two reservoir/wells.  Fluid was a very light brown, but is otherwise well over 15 years old.

I figured I'd start by sucking fluid out of the reservoir with a baster and putting new fluid (DOT 3/4).  Figured I'd bleed the brakes.  Never done this on a drum brake.  I assume that this is done via the wheel cylinder?

Anything I'm doing thats egregiously wrong?  Am I missing something obvious?  Should I be looking in other places?

Thanks.

K. A. Young
1967 Camaro SS 350
Fort Collins, CO

TRLAND

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Re: Soft brakes -- Fluid level, bleeding, and shoes (drum, pb)
« Reply #1 on: June 25, 2016, 01:17:37 AM »
The only obvious thing you're missing is the obvious.  Shoes are old and worn, fluid is old and low, brake lines are old and possibly rusted out, brake parts are probably rusty and dirty. If all of that stuff is really original and 49 years old with 50,000 miles then it needs a complete brake rebuild to be safe on the road.  I don't want to be in front of you going 55 mph if I have to stop fast!  I was a noob when I did mine and it isn't that hard. Just take your time and do it right or find someone that can do it for you. Do a complete brake rebuild on all 4 wheels, possibly even replacing the cylinders, check and replace any hard brake lines needing it, replace all soft lines.  Drain ALL of the old fluid out at all 4 corners and flush some new fluid through before bleeding all the air out.  There are youtube videos for all of this and lots of help here and at Team Camaro.
Mike in Northern Illinois
1967 RS 327

67L48

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Re: Soft brakes -- Fluid level, bleeding, and shoes (drum, pb)
« Reply #2 on: June 25, 2016, 04:52:53 PM »
Yeah, sounds like a plan.  It appears that for ~$130, I can get new shoes, all new springs, new adjustment kits, and wheel cylinders for all 4 corners.  That seems like all the parts in there, other than the backing plate.  I'll examine the hard lines and replace as needed.  Youtube videos seem pretty good ... not sure what people did before internet/youtube!

I've looked at the main auto parts stores and the ACDelco parts.  They all seem the same.  Wearever (advance auto parts) = Duralast (auto zone) = ACDelco.  Even the pictures are often the same (esp with the spring kits).

Thanks.

K. A. Young
1967 Camaro SS 350
Fort Collins, CO

Spooky

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Re: Soft brakes -- Fluid level, bleeding, and shoes (drum, pb)
« Reply #3 on: June 25, 2016, 06:28:06 PM »
If you are going to do all of that, replace the hoses as well. they might be swelling and giving you a soft pedal. Do it once, do it right.

Scott

67L48

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Re: Soft brakes -- Fluid level, bleeding, and shoes (drum, pb)
« Reply #4 on: June 26, 2016, 02:35:46 PM »
Now I'm rethinking the replacement strategy.  I pulled the wheels off the driver side of the car yesterday.  The brakes looked great.  A little dusty, but not bad.  The colors of the springs were still visible.  Pads were thick.  All the lines looked great.  Some of the hard lines had gunk on them, but the lines were solid, free of rust, looked new. The wheel cylinder actuated the pads just fine.

I got the car in 1989 with 34,000 original miles.  I verified that brakes were changed in the early 1990s.  So, as I suspected, the pads and components didn't decompose over 20,000 miles.

Maybe there's another reason to change the pads?  Even though the pads are quite thick, should they still be replace due to age?

Right now, I'm thinking fluid and bleeding ... but I can still change components if that's necessary ... it's just that everything looked and moved great.  I'll see if I can post pictures.

K. A. Young
1967 Camaro SS 350
Fort Collins, CO

69Z28-RS

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Re: Soft brakes -- Fluid level, bleeding, and shoes (drum, pb)
« Reply #5 on: June 26, 2016, 03:21:17 PM »
If your brake pad material is thick (thicker than 3/16"), then just scuff the glazed pad surface and inside the drums wtih 80 grit sand paper.  If the brake material is around 1/8" thick, then replace them (they are more than half worn at this level).

Replace the rubber hoses for sure, all three... the rubber is likely to be breaking down on the inside.  Clean inside the steel lines with alcohol..  air blow thru them to dry them. 

Remove the wheel cylinders to check/clean/rebuild as necessary.   

Remove the master cylinder to check/clean/rebuild as necessary. 

Put it all together and bleed thru with clean good brake fluid.  (I like using silicone - DOT 5 - but you should only do this IF you rebuild all the wheel and master cylinder with new rubber seals)...  Other wise use the synthetic (DOT 4?) brake fluid.
Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
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KurtS

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Re: Soft brakes -- Fluid level, bleeding, and shoes (drum, pb)
« Reply #6 on: July 18, 2016, 03:01:42 AM »
It sounds in good condition, but the master sounds like it's possibly leaking a little.
Scuff the drums.
Replace the soft lines.
Use DOT3 or 4 - it's all the same.
Then go after the master if it's not all good.
Kurt S
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bcmiller

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Re: Soft brakes -- Fluid level, bleeding, and shoes (drum, pb)
« Reply #7 on: July 18, 2016, 03:59:18 AM »
What did the drums look like? Did you measure thickness?
Bryon / 1968 Camaro SS 396 - now 468 ci, M21, 12 bolt
Looking for 68 Camaro with body number NOR 181016