Rear Brakes Locking Up

[Andronikos]

And post some pics of the brake system we're blindly diagnosing!

 

[Andronikos]

That is it. Exactly the same as the image I posted in comment#34.

 

[DoubleDingo]

That is it. Exactly the same as the image I posted in comment#34.

I didn't click the google link because it's not your truck, and showing a general pic of a similar MC and not your actual MC or your front discs or your rear drums doesn't tell us anything but what is on someone else's truck. And judging by that pic you just shared, the small line is on the wrong reservoir, as the big reservoir is for the fronts. When we ask for photos of your setup, that's what we need to see. If you're not near your truck, simply say so. If you don't have a camera, say so. If your truck is wanted by the Feds or is in the witness protection program and can't be seen in photos, say so. We're trying to help. We're not getting anywhere with just words from you.

 

[Ricko1966]

That is it. Exactly the same as the image I posted in comment#34.

You didn't post that pic on #34 you posted a link to picture on Amazon This is the first pic you've put up,period.There have numerous requests for pics. Pics of the rear shoes assembled,pics of the backs of the calipers,showing bleeder orientation etc. Sorry posting pics is such a problem,and getting an attitude about the ONLY pic you've bothered to post,doesn't really make people want to help you. Take it to a shop,pay someone that knows what they are doing to fix it. I guarantee you I could fix it,without a forumn and zero parts installed that didn't come factory.

 

[Grit dog]

The truck was incomplete when I bought it, and the entire brake system was, IMO, in bad shape. It didn't run when I bought it so I have no before/after reference. I have no reason to lie to anyone on this forum. I'm simply seeking insight or advice. If you have some of that please let me know, but don't call me a liar.

New: Master cylinder
Steel lines from master to prop valve
Steel lines from prop valve to each front caliper rubber line
Both front caliper rubber lines
Both calipers
Both front rotors
4 front brake pads
Steel line from prop valve to frame above differential
Rubber line from frame to the brass "T" fitting
Steel lines from "T" fitting to each rear wheel cylinder
Both rear wheel cylinders
All 4 rear brake shoes
All the rear spring, parking brake, hold down hardware
Both rear drums
The rubber pad on the brake pedal
All parking brake cables, balancer, etc

Used: Proportioning valve
Brass "t" block at rear differential
Brake booster

It’s unfortunate you’re providing very complete, coherent and fairly knowledgeable input to try to solve your issue and there are a couple select folks responding in some weird accusatory and somewhat off topic or off base manor. Oh well, that’s the internet….
From the info you provided, there is nothing obvious or glaring I’ve seen to cause this.
Couple things I noticed, the MC pic you provided has the front reservoir in front and I think you said you plumbed the front line to the rear position on the MC.
Could also be why I think you mentioned the fronts don’t seem very aggressive. Worth pinching off the rear brake hose or disconnecting and plugging the rear line imo to see if the front brakes are doing real work. (Back to are the lines switched at the MC. With all new hard lines, may have an anomalie or the wrong hard line that only hooks to the wrong port.)
IF you are convinced that is not the issue and also the front brakes are working great, have you simply backed down the adjusters in the rear a smidge and seen if it helps? (another way to test the fronts, new hardware makes it easy to adjust the rear brakes to real loose and see how well the fronts work. FYI with NO rear brakes, fronts should still grab HARD, pull the nose of the truck down and stop the vehicle relatively “normal.”)
Or the prop valve could be not propping like it should. Lol. Maybe worth throwing the $100+ at that if other tests prove to not reveal the problem.
This is a pretty unique situation IMO. Drum brakes aren’t rocket science but this is perplexing.
Good luck!

 

[ASPEC]

Read the whole thread... if this was asked already I apologize...

What product did you use to clean the new rear brake drums BEFORE you installed them?

What brand of rear brake shoes did you use?

 

[Broken85]

If you are still not sure if you have the front and rear in the right spot, trace them from the MC to the Portioning Valve. If they are correct, I’d say change the PV.

 

[Grit dog]

Looking at that pic I think you might maybe have your home made brake lines reversed.

 

[Ricko1966]

I have the rear port of the master, the small line, feeding the front brakes, and the front port of the master feeding the rear brakes. Is that right or do I have it backwards?

Yes you do have it backwards.

 

[AuroraGirl]

Having the lines reversed would explain the difference in volume and pressure that could make those rears lockup and fronts not do much

But id like to point out, that, his answers have been good and complete, but the issue was found only AFTER he posted a photo. Which he wouldnt do. If this fixes his issue, hes probably fine all elsewhere plus the things I mentioned about the filter for the booster

If hes got problems after, he should show us the more components but im glad we finally got to see. at least the MC is right too

 

[Andronikos]

Read the whole thread... if this was asked already I apologize...

What product did you use to clean the new rear brake drums BEFORE you installed them?

What brand of rear brake shoes did you use?

LOL! Brake clean. Raybestos

 

[Andronikos]

Having the lines reversed would explain the difference in volume and pressure that could make those rears lockup and fronts not do much

But id like to point out, that, his answers have been good and complete, but the issue was found only AFTER he posted a photo. Which he wouldnt do. If this fixes his issue, hes probably fine all elsewhere plus the things I mentioned about the filter for the booster

If hes got problems after, he should show us the more components but im glad we finally got to see. at least the MC is right too

It's not my fault you can't understand written English. Get off my thread.

 

[Andronikos]

Yes you do have it backwards.

Thanks for a real answer.

 

[Andronikos]

Looking at that pic I think you might maybe have your home made brake lines reversed.

Thanks. That was easy.

 

[Andronikos]

It’s unfortunate you’re providing very complete, coherent and fairly knowledgeable input to try to solve your issue and there are a couple select folks responding in some weird accusatory and somewhat off topic or off base manor. Oh well, that’s the internet….
From the info you provided, there is nothing obvious or glaring I’ve seen to cause this.
Couple things I noticed, the MC pic you provided has the front reservoir in front and I think you said you plumbed the front line to the rear position on the MC.
Could also be why I think you mentioned the fronts don’t seem very aggressive. Worth pinching off the rear brake hose or disconnecting and plugging the rear line imo to see if the front brakes are doing real work. (Back to are the lines switched at the MC. With all new hard lines, may have an anomalie or the wrong hard line that only hooks to the wrong port.)
IF you are convinced that is not the issue and also the front brakes are working great, have you simply backed down the adjusters in the rear a smidge and seen if it helps? (another way to test the fronts, new hardware makes it easy to adjust the rear brakes to real loose and see how well the fronts work. FYI with NO rear brakes, fronts should still grab HARD, pull the nose of the truck down and stop the vehicle relatively “normal.”)
Or the prop valve could be not propping like it should. Lol. Maybe worth throwing the $100+ at that if other tests prove to not reveal the problem.
This is a pretty unique situation IMO. Drum brakes aren’t rocket science but this is perplexing.
Good luck!

Thanks for a the insight, and for being a gentleman. I'll do these things as soon as I get time.