Emergency Brake Cable Replacement Troubles 1996 3/4Ton 4x4

[tinkering]

Chevy 3/4 Ton, 4x4, Exd cab (2 door), long box, semi floating axles, GVW 8600

I hope someone has the patience to look at this one, and address a couple of things.
I don't know where to start, except I am flabbergasted

I have gone through 3 sets of different rear brake cables until finally I have some results. The measurements and slight differences between the cables are enough to break my poor mind. The parts guy finally went to the dealer with my VIN. He crossed the OEM numbers to the Raybestos numbers and I put those two cables on the left and right rear.

The return springs on these new correct cables are 10" long; the return springs on the originals are 7" long. When the cable is installed and attached to the emergency brake arm, the longer spring bows out, until the slack is drawn out by shortening the cable at 'the equalizer'. I am concerned that the spring might be able to totally compress, and in doing so limit the further travel needed to apply the brakes as the shoes wear down. Is it a feasible idea to cut the spring back some? Why would the replacement have a 3 inch longer return spring? What is the main purpose of the those coily springs?

'The equalizer' seems like a retarded design to me; or else there is a part missing or something. The original right rear cable end that went into the equalizer was a dome shaped plug on the end of the adjuster rod, that kinda hooked into the slots on the sides of the equalizer; there was a small crimp style hose clamp holding things together. There was no way that I could see to adjust the length of the adjuster rod (I may have to draw an illustration). None of the replacement cables had this domed plug; they all came with two nuts on the threaded adjuster rod. I have figured out a way to hook into the slots on the equalizer using a washer behind the forward adjuster nut; I hold it together with a small threaded hose clamp. All is fine there except I can not figure out how to tighten the adjuster nut when it is sheltered inside that goofy equalizer. Is there a piece missing on that equalizer, which would allow access to the adjuster nut; or a special tool or something?! I think I might be able to make a spacer out of a piece of steel tube, that will bring the adjuster nut out of that sheltered area, and into the wide open area at the center of the equalizer. Does any of this make sense?

Also, if the overall cable length is too much to get the E brake pedal up, I dreamed up a way to shorten it: cut a 3 or 4 inch long piece of 1 inch steel or aluminum strap; cut/grind a number of slots in it (like a course comb. Run the cable in and out of the slots in a serpentine fashion; thus using up some of the length.

[tinkering]

If someone doesn't come up with some feedback on whether I should cut those springs down a bit or not, I am going to just slap the whole thing together and hope for the best Just because the old springs were shorter doesn't mean that they were the right ones; someone may have just installed the wrong cables in there out of shear frustration (I don't know where my patience have come from through this job). One would think the numbers that came up via the VIN should be the right ones.

[jdl]

Sorry, I have no feed-back for you. I've never run into that problem. good-luck.

[MT-2500]

Originally Posted by tinkering

If someone doesn't come up with some feedback on whether I should cut those springs down a bit or not, I am going to just slap the whole thing together and hope for the best Just because the old springs were shorter doesn't mean that they were the right ones; someone may have just installed the wrong cables in there out of shear frustration (I don't know where my patience have come from through this job). One would think the numbers that came up via the VIN should be the right ones.

If they will work without cutting leave them as is.
I would hook them up with shoes on both sides and drum on other side and apply foot brake.
If shoes pop out enough for a good emg. brake.
If not shorten springs.

let us know how it goes.

[tinkering]

Originally Posted by MT-2500

If they will work without cutting leave them as is.
I would hook them up with shoes on both sides and drum on other side and apply foot brake.
If shoes pop out enough for a good emg. brake.
If not shorten springs.

let us know how it goes.

Do you mean you would put only the passenger side drum on, and then step on the emergency brake pedal while observing the shoe travel on the driver's side? I will try that, and then I will put the other drum on as well, to see if I can attain a high pedal with the amount of adjuster rod I have. I will post the results.
Thanks

[Schurkey]

Originally Posted by tinkering

The return springs on these new correct cables are 10" long; the return springs on the originals are 7" long.

I am hoping that the three-inch difference in the length of the brake cable springs is because your old ones have compressed over time. I suppose this is possible, but it does make me nervous.

Originally Posted by tinkering

What is the main purpose of the those coily springs?

They help return the cable (and the park brake mechanism attached to the brake shoes) to the at-rest position when the park brake is released.

Originally Posted by tinkering

'The equalizer' seems like a retarded design to me; or else there is a part missing or something. The original right rear cable end that went into the equalizer was a dome shaped plug on the end of the adjuster rod, that kinda hooked into the slots on the sides of the equalizer; there was a small crimp style hose clamp holding things together. There was no way that I could see to adjust the length of the adjuster rod (I may have to draw an illustration). None of the replacement cables had this domed plug; they all came with two nuts on the threaded adjuster rod. I have figured out a way to hook into the slots on the equalizer using a washer behind the forward adjuster nut; I hold it together with a small threaded hose clamp. All is fine there except I can not figure out how to tighten the adjuster nut when it is sheltered inside that goofy equalizer. Is there a piece missing on that equalizer, which would allow access to the adjuster nut; or a special tool or something?! I think I might be able to make a spacer out of a piece of steel tube, that will bring the adjuster nut out of that sheltered area, and into the wide open area at the center of the equalizer. Does any of this make sense?

I want to see photos. This scares me. The park brake cables that I removed from my 3/4 ton axle have nothing more than small cylindrical steel ends attached to the equalizer end of the cable--no "domes", no adjuster rods. They were made the same as the half-ton park brake cables, except they were much longer because the donor vehicle was an extended-cab, and my truck is a regular-cab.

If your truck is like mine, there's only one adjuster for the park brake system; you cannot adjust left and right park brakes separately. All the adjustment is in the equalizer, not in the park brake cable.

Originally Posted by tinkering

Do you mean you would put only the passenger side drum on, and then step on the emergency brake pedal while observing the shoe travel on the driver's side? I will try that, and then I will put the other drum on as well, to see if I can attain a high pedal with the amount of adjuster rod I have. I will post the results.
Thanks

I'd expect that your 3/4 ton pickup has duo-servo rear brakes (adjuster at bottom, between shoes.) My '88 half-ton had the (crappy) twin leading shoe style brakes (adjuster just below the wheel cylinder) until I stuffed a 3/4 ton semi-floating rear axle under it.

When working with duo-servo style brakes having a park brake, ADJUST THE SERVICE BRAKES FIRST. If you have to, back off the park brake adjustment so that the top of both shoes rest against the anchor pins, on each side of the axle. THIS IS IMPORTANT! If the shoes on both sides (both rear wheels) DON'T contact the anchor pin with the brakes not applied, the park brake is adjusted too tightly, or the brakes are assembled incorrectly, or the brake fluid is restricted from returning to the master cylinder. In short, something is wrong.

The service brake pedal should be high and firm when the service brake is applied, and the shoes must rest against the anchor pins when they're not applied. AFTER the service brakes are adjusted properly with the star-wheel at the bottom, between the shoes, THEN start adjusting the park brake cable(s) as required.

I go so far as to lift the rear axle off the ground, adjust the service brakes, install the drums with a lug-nut or two on each, then start the vehicle. I throw it into gear, and make some "stops" both forward and reverse. Usually, I need to tighten the adjusters some more, because actually using the brakes a few times provides better shoe alignment than just assembling the parts and sliding the drum on. When I'm satisfied that the service brake pedal is appropriately high and firm, only then do I move on to the park brake cable adjustment.

[tinkering]

Originally Posted by Schurkey

I am hoping that the three-inch difference in the length of the brake cable springs is because your old ones have compressed over time. I suppose this is possible, but it does make me nervous.
It doesn't seem like it is because it has 'compressed' over time. I can only assume that the old cables were the wrong application that someone made fit.


They help return the cable (and the park brake mechanism attached to the brake shoes) to the at-rest position when the park brake is released.
With the extra length they will sure do that.


I want to see photos. This scares me. The park brake cables that I removed from my 3/4 ton axle have nothing more than small cylindrical steel ends attached to the equalizer end of the cable--no "domes", no adjuster rods. They were made the same as the half-ton park brake cables, except they were much longer because the donor vehicle was an extended-cab, and my truck is a regular-cab. In that case there would definitely have to be parts missing from this equalizer, because there is no way to make an adjustment with this equalizer unless I make my proposed changes (adding the spacer etc.) Maybe they were different, US v/s Canadian production? We will get pictures for you; it is 20 below again today.

If your truck is like mine, there's only one adjuster for the park brake system; you cannot adjust left and right park brakes separately. All the adjustment is in the equalizer, not in the park brake cable.
That is how mine is too.

I'd expect that your 3/4 ton pickup has duo-servo rear brakes (adjuster at bottom, between shoes.) My '88 half-ton had the (crappy) twin leading shoe style brakes (adjuster just below the wheel cylinder) until I stuffed a 3/4 ton semi-floating rear axle under it. Yes, it has duo-servo.

When working with duo-servo style brakes having a park brake, ADJUST THE SERVICE BRAKES FIRST. If you have to, back off the park brake adjustment so that the top of both shoes rest against the anchor pins, on each side of the axle. THIS IS IMPORTANT! If the shoes on both sides (both rear wheels) DON'T contact the anchor pin with the brakes not applied, the park brake is adjusted too tightly, or the brakes are assembled incorrectly, or the brake fluid is restricted from returning to the master cylinder. In short, something is wrong.
Both shoe tops, both sides, are resting on the big anchor pin when the brakes are not applied.

The service brake pedal should be high and firm when the service brake is applied, and the shoes must rest against the anchor pins when they're not applied.

AFTER the service brakes are adjusted properly with the star-wheel at the bottom, between the shoes, THEN start adjusting the park brake cable(s) as required. Great, that's what I figured.

I go so far as to lift the rear axle off the ground, adjust the service brakes, install the drums with a lug-nut or two on each, then start the vehicle. I throw it into gear, and make some "stops" both forward and reverse. Usually, I need to tighten the adjusters some more, because actually using the brakes a few times provides better shoe alignment than just assembling the parts and sliding the drum on. When I'm satisfied that the service brake pedal is appropriately high and firm, only then do I move on to the park brake cable adjustment.
I have it up on axle stands, so I did it your way; it worked well. I had help today too After the adjustments were made there is 4 to 6 inches of E brake pedal before it applies the brake tight.

I replied in red within the text of your quote so my reply wouldn't be so confusing.
Thanks a bunch.

[j cAT]

do the pictures again , not working for me.

[tinkering]

Originally Posted by j cAT

do the pictures again , not working for me.

I'll try uploading one photo at a time; per reply.
Hover over the thumbnail to read further description.

The 7 inch return springs that I found in there did not bulge out like this. It made me wonder if these 10 inch springs were going to work... they appear to be working fine so far.

[tinkering]

Originally Posted by Schurkey

I want to see photos. This scares me. The park brake cables that I removed from my 3/4 ton axle have nothing more than...

There are11 photos in all. I am not sure what the problem is with uploading them; I will keep trying.

Hover over the thumbnails to read further description.

When I attached and adjusted the cables at the equalizer end, a lot of the slack was taken up. At present it appears as though the springs are not totally compressing before the E brake pedal is on all the way (I was initially concerned about this).

[tinkering]

pics 3, 4
Hover over the thumbnails to read further description.

The equalizer configuration that I found on the vehicle allowed for NO adjustment. This is a mystery to me. The dome shaped plug basically hooked into the equalizer (the same way I eventually hooked the adjuster washer and spacer into place; pics 9 and 10 show this), with a squeeze clamp holding it together.

[tinkering]

pics 5, 6
Hover over the thumbnails to read further description.
I could not get a wrench on the adjuster nut.
#5 equalizer was not allowing access of adjuster nut.jpg

I used this spacer sleeve to reconfigure the equalizer/adjuster.
#6 protective steel sleeve from old cable at differential bracket.jpg

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pic 7
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Not installed yet is the larger washer outside of the equalizer, which spans the full width of the equalizer and allows the lock nut to function. This washer can be seen in pic #11
#7 steel sleeve used as spacer.jpg

#8 flexing allows access to adjuster nut.jpg

[tinkering]

pic 9
Hover over the thumbnail to read further description.

Put lots of grease on everything during final assembly.

[tinkering]

pics 10, and 11 of 11
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#10 washer seated on shoulders.jpg

#11 adjusting cable while flexing equalizer; see clamps on both ends of equalizer.jpg
See larger washer is in place, to accommodate the lock nut function. When finished with the adjustment, I really packed grease on and into the whole thing (not shown in picture), so it won't rust up so soon and I can easily make future adjustments.
(I'm wearing the gloves because it was 30 below that day