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Post by destructiondylan on May 6, 2014 12:44:41 GMT -5
Hey guys. Building a 75 doba this year. Ony gonna run rear brakes. Last night was doing a couple things under the hood and noticed both brake lines from the master looked like they ran into a proportioning valve lookin thing below the master a ways. If I pinch off the front brake line after the master and then cut the brake lines to the front calipers is it gonna mess with my rear brakes on a count of that valve in there? Do u guys remove it and run ur brake lines from the rear line straight to the master? Also I see some of you are getting rid of the booster. Is the lesser braking power an issue by going to manual brakes like that? Thanks in advance for any and all responses.
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dm440c
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Post by dm440c on May 7, 2014 11:39:08 GMT -5
I think most of that is covered here already but I'll go over it anyhow-
the reason for removing the booster is because space under the hood in any Mopar is tight and the booster is great for smashing headers and valve covers. Yes you will lose pedal feel when you go to manual rear drums only. If that really bothers you then you may have to explore other options (such as fabricate a setup that mounts inside the car) or accept having smashed headers and valve covers.
The prop valve has 2 lines in from the master and 3 lines out- one to each front caliper and one to the rear axle. You could block off or loop the two that go out to the calipers but what I do is toss the prop valve, route both lines from the master into a tee fitting, and send that back to the rear axle thorugh the inside of the car to protect it. I find this gives the best pedal feel.
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Post by destructiondylan on May 7, 2014 12:31:39 GMT -5
The t for the master lines to the rear brakes is an awesome idea. Thanks a ton! And that booster sure is in a tight spot. After closer inspection last night it's definately gonna go, not only for header clearence but for steering shaft clearence as well. And I'll definately be runnin the line inside the car, the factory line looks really venurable to getting caught on something. I read this entire thread and couldn't find my answers, thanks for the response.
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Post by destructiondylan on May 7, 2014 12:50:26 GMT -5
Another question about the steering. Milk be running a stock column and I took the steel plate off the base of the column that bolts to the firewall and am gonna run a slider shaft with a u joint. I still have the stock shaft in there right now and the column is pretty sloppy. I remove the plastic break aways at the too of the column and bolted it directly to the firewall bracket bu it still moves around quite a bit. Will the slider shaft/u-joint combo be more rigid? I was also thinking of finding a dual u joint slider shaft and then making a brace for the base of the column to the firewall. You think this would be better or just stick with the single u-joint slider setup? I don't wanna over complicate things. My best friends dad owns the local wrecker and is my sponsor so parts aren't really an issue.
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dm440c
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Post by dm440c on May 8, 2014 10:06:59 GMT -5
I have pics up somewhere, I think in this thread, of how I do it. Just one u joint and chain the column to the saddle.... it floats a little but that is what preserves it from binding up when things get bent all wonky.
When designing a non-rigid shaft you just have to be careful not to have more degrees of freedom than fixed points. Figure that the connection at the steering box is one fixed point, then a u joint, then another fixed point at the top and that is a system that is sufficiently constrained. To add more components you then go from there, i.e., if you add a second u joint then you will need two more fixed points to keep it from flopping over center and binding up. A slider section will require some thought into how it is constrained. Stuff like that.
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Post by destructiondylan on May 9, 2014 15:34:14 GMT -5
I saw your pictures of the slider setup and that's what I'm gonna end up going with. I was just worried the column would be flopping around too much because mine is banging the top and bottom of the hole in the firewall. But after looking a little closer the rag joint is half torn so it's really loose. Im sure once I get the u-joint and slider welded in there, there will be a lot less flopping around. Thanks for the help
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dm440c
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Post by dm440c on May 12, 2014 10:06:58 GMT -5
yes, and I usually make the hole in the firewall bigger by relieving it all the way up to where the brake master is mounted. I think that can be seen in the pic.... ?
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Post by derbyman180 on Jul 2, 2014 20:30:07 GMT -5
Just got a used 8 3:4 rear for cheap. The problems is that there is no brake hardware at all besides drumes. Can any body give me a schematic of where the brake hardware kit and the brake shoes would go. Not too familiar with drum brakes any pictures or diagrams would be great. There will also be new wheel cylinders on it as well but the new ones I got are also a little different. The old one has like a 2 prong end that I think would attach to the brake shoes but the new one is just a flat cylinder one. Any help would be great thanks guys.
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Post by seventyonehemicuda on Jul 2, 2014 22:47:40 GMT -5
Just google "Mopar 8.75 brakes" image search.
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Post by derbyman180 on Jul 3, 2014 10:59:07 GMT -5
Do I need to keep any of the e brake assembly? And what other rear would have the same brake parts as well . Some of the pieces are missing
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Post by Imperialist on Jul 3, 2014 13:41:24 GMT -5
Just take the whole backing plate that is loaded with brakes and brake drums off the rearend that you are pulling from the car...
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Post by STROMI 121 on Jul 4, 2014 22:01:45 GMT -5
You can throw all the e brake stuff in the trash but it require another spring the same length as the long one and a hole drilled in the other shoe to match the other side.
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dm440c
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Post by dm440c on Jul 6, 2014 7:42:49 GMT -5
I just chuck the e brake stuff completely, no additional mods needed.
There is a lot of info in the Mopar brakes & steering thread I do believe, including discussion about the different sizes of drums and other things you need to watch for.
Generally though you need:
- shoes - drum - wheel cylinder - star wheel adjuster assy (cable, lever, star wheel & spreader, pivot) - springs - shoe retainers
All Mopar axles from the 60's through the 80's use the same design and the only thing that is really different is the diameter and width of the shoes, which changes the size of the components. But the design is the same.
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Post by STROMI 121 on Jul 7, 2014 15:45:10 GMT -5
This is a 12 bolt but you get the idea.
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Post by 262markm on Jul 8, 2014 3:06:42 GMT -5
What line fits into a shocker box and a chevy pump no lines were there for me to work with
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