So, I hear you tried the clamp test and got a hard pedal, and unclamping one hose at a time produced 1.5in travel in the back, and 2.5in or so at the fronts.And with no one front much worse than the other. Good news, Everything is good up to the wheel cylinders at this point.And the rear, surprise, is likely, ok.
So now we have to figure out; is there air inside the w/cs or is it adjustment or other.
Lets talk about "other" first. This would be; incorrectly assembled parts, wrong parts, or incorrectly machined drums. The first two are on you. You need to be confident that you did your part right.The machining is on the machine shop, and its hard to screw up, so Im gonna assume, for the moment, everybody got it right. Ok then.
-You have 2 options; First, leave the rear hose clamped, but un-clamp the fronts, then
- Option 1) crank the adjusters out hard.Then step on the brakes a couple of times to center the shoes. Not hard, just a couple of stabs.Then see if the adjusters will take a couple more clicks. Now go check for hard pedal.You will have one of three results. 1) hard pedal/no travel. 2) spongy pedal/ lots of travel. or 3) springy pedal/wee bit of travel. The pedal should be fairly hard with only a wee bit of travel.A hard pedal means the hydraulics are good. If the pedal is hard with springy feel,not spongy,that might be normal. The springyness could be due to flexing of; the old hoses,out of round drums,drums not machined concentric with the center register, or drums moving around on the hubs.Of these,the most likely is/are the hoses.I wouldnt be too concerned about that springyness just now.If, however, theres still quite a bit of travel, with a spongy feel,there may be a tiny bit of air still trapped in the w/c.To find out which one use the clamp test, again.Then bleed it out. I use the words springyness and spongyness because thats how my brain interprets the feel.I cant actually define these feelings to you. However you already know what spongyness feels like(having bled the brakes), so the springyness will be slightly different.When/if you encounter it, you will recognize it. The pedal travel is different as well.
-Option 2) You will need a couple of small, HD,C-clamps, Im guessing about 3 or 4 inchers. Fully diss-assemble the front brakes.Remove the dust seals, and pusurods, from the w/cs. Put your clamps on the w/cs, such that the pistons cant come out.Now go check the pedal.Hard and no travel means hydraulics are A-ok.Spongy? You know whats next. Isolate, retest, bleed, repeat as necessary. Springyness now can only be the hoses. Ok dont forget to remove all the clamps and reassemble..
-If you have to go to option 2, and get a hard pedal, then the problem is purely mechanical, and inside the drums.The number one most likely reason is adjustment.Next guess would be flexing drum. I kinda ruled that one out when you said that the shoes were radiused to the drums. Id like to revisit that.The shoes need to be fitted to the drums. If you take an off-the-shelf shoe set and bench fit them into a new un-machined drum, there would be little to no rocking motion. However, putting those same shoes into a .060 machined drum will get you a wee bit of rocking. The shoe is now contacting the drum in a small patch somewhere as opposed to full contact.If you install it this way, one of three things will happen; 1) when the w/c pushes the shoes out, the shoes will bend a tiny amount to conform to the drum, or 2)the drum will distort to conform to the shoes. or 3) nothing at all because all the parts are able to withstand the forces.Either of the first 2 actions will result in additional pedal travel. A very similar result will be had if the adjusters are backed off too far;instead of having a full contact to the drum, you might get contact in only 70 or 80%.
All of this flex talk is mosly mumbo-jumbo though. It only manifests when the vehicle is at rest. As soon as the drum is spinning and you apply the brakes, something else happens; self-energization. Another thing that happens is break-in. Having the shoes reground to fit the oversize drum mosly just reduces the break-in period,increases the initial braking ability,reduces pedal pressure to get the car stopped safely, and makes a happy customer.
-Im gonna go out on a limb here and guess that after you perform option 1 youre gonna get a hard pedal/no travel. meaning everything is normal, and all you needed was a bit more adjustment.
-Adjustment;Ill tell you what works for me. I crank those adjusters out til the wheel drags pretty good.Then I go stab the pedal a few times.Then I go back and crank a few more clicks in. Then I go stab the pedal a couple more times.What Im trying to accomplish is to get the shoes centered. It usually takes 2 or 3 cycles to get this done.Then I back the adjusters out until they turn a little easier( I always clean them before reassembly and lube with anti-seize, so I know they will turn easy).Then I crank them back in til they tell me to stop.Huh?Well yeah after a few hundred jobs they kinda talk to you. Ok, but for you, its like this;Imagine a 3/8 bolt clamped in a vise on the flats. Imagine 2 nuts screwed on a ways. Screw them together, finger tight. Put a wrench on each one.Anchor the one.Tighten the second to it with the wrench, like maybe 5 or 6 ftlbs.You get how that feels? Its like at a certain point, bam, the wrench just stops.Thats the feeling.From there I usually back off a few clicks. maybe 6? Now I grab the tire and give it a turn.If I get it just right it will turn with a drag. Ill feel it and hear it rubbing.I like it when Im close. Im gonna say I like in the neighborhood of a ten pound drag. That is if you hung ten pounds on the tire parallel to the ground it would just turn the wheel.Then I set them all that way. Some might say thats too tight, then back them off til no drag and live with the long pedal travel. Heres my take;The shoes need to be broke in anyway, so lets get it over with. And the hard pedal/short travel makes the customer happy. A week from now, the self-adjusters will have it all be sorted out.I do this on a new install.On used parts I back off a bit more.Or you could do what Bill does(previous post).Thats a fine way to to do it.
Ok, so I think thats it for now.Oh wait.Now its time to change those hoses. So, all the best to you.
....I checked RockAuto an Autozone. The M/C is the correct Drum/Drum with equal reservoirs and a Bore Size (In): 1.03125 Inch. The front W/C is 1 3/16 and rear is 15/16. Ill report back next week.
