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  #11  
Old 10-26-2023, 12:25 PM
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All of the above and my 2 cents are cups in master are allowing fluid to bypass internally and won't necessarily leak externally, but cause the spongy feel. Also, the rear flex hose sounds like it is collapsed, causing the restricted flow and will expand under pressure, again can cause spongy pedal.
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  #12  
Old 10-26-2023, 02:40 PM
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Quote:
Originally Posted by PeteLeathersac View Post


All above plus pull frt. calipers and service slide systems also remove drums and confirm rear wheel cylinders Ok both directions + adjusters free and wound out as far as possible but you can still get drums on/off.
Next, elevate rear and bleed system, RR first on to LR and RF w/ LF last also if weak pressure bleeding, consider flex lines may be internally collapsed whether they look good externally including rear flex if low/no pressure @ wh. cyls.
Best of luck!

~ Pete

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----Forgot about the flex lines!....Bill S
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  #13  
Old 10-27-2023, 02:22 AM
Big Block Bill Big Block Bill is offline
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Quote:
Originally Posted by enio45 View Post
Sounds like a good brake overhaul would be best approach......one can spend alot of time on one item or another, hoping to identify the issue etc.

Comprehensive brake overall might be in order - new rubber lines all the way around - new proportioning valve, pull and rebuild all brake calipers - fit and rears......

flush and clean system - see what we have.

i was trying to avail this level of effort, but all the points / suggestions above drive me to think this is the best approach. related to the booster and master cylinder - maybe a rebuild of the master is in order - i have good boost from the booster - so that will be the only think i dont touch.

sounds??????????
I would suggest before you do anything, go buy (2) new wheel cylinders for $20.00 each from a NAPA store and replace those first. If I remember correctly, an 1987 El Camino had 3/4" wheel cylinders and they were known for the pistons sticking internally, quite common for causing a car to not being able to lock up the brakes in a panic stop situation. A very cheap start before you do all that proportioning valve & caliper stuff.

Bill
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Old 10-27-2023, 02:46 AM
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Understood - and thinking thru this - im getting more comfortable that i dont have solid rear brakes....so from that perspective - prop valve back may be the issue. Easy enough to pop in 2 new wheel cylinders in the rear and see what happens.

On this topic - i have seen the flexible brake lines collapse on the inside on a variety of cars - is there any rule of thumb when it is wise to change out the flexible lines?
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Old 10-27-2023, 02:47 AM
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Quote:
Originally Posted by enio45 View Post
Understood - and thinking thru this - im getting more comfortable that i dont have solid rear brakes....so from that perspective - prop valve back may be the issue. Easy enough to pop in 2 new wheel cylinders in the rear and see what happens.

On this topic - i have seen the flexible brake lines collapse on the inside on a variety of cars - is there any rule of thumb when it is wise to change out the flexible lines?

You're going to have to bleed the rears after the wheel cylinder replacement, NOW is the time to change that hose too.
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  #16  
Old 10-27-2023, 02:49 AM
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yes why not at that time - Ill order up some parts and plan the work next weekend.
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Old 10-27-2023, 03:59 AM
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Get the GOOD cylinders from NAPA that Bill mentioned. Don't order some chinese crap off amazon or cpp. They have the brake hose too.
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  #18  
Old 10-27-2023, 05:16 AM
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I personally would start with just the brake hoses. Yes, it will require another bleeding if it’s not the issue but in my experience it is the place to
start.

Jason
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Old 10-27-2023, 11:55 PM
Big Block Bill Big Block Bill is offline
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With a 20,000 mile car? I've seen hoses cause a wheel to lock up and not release when they deteriorate, but not cause a car to not panic stop, that's normally caused by a stuck caliper or wheel cylinder. I still bet it's the wheel cylinders. But once again, "I'm just Sayin" Bill
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  #20  
Old 10-28-2023, 12:02 AM
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OK, well parts ordered - say next weekend project and see what happens.

Im going to replace the wheel cylinders rear, rear rubber hose and for i also purchased a set of across the axle brake lines - in the event we have issues getting the other lines off easily, ill have a backup plan immediately.

Appreciate all the advice guys!
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