failed emissions and brake issue...

[ashman]

reposting this here for more eyes.

according to the inspection report, my ps rear brake is hardly working at all. I assumed it was out of adjustment, but after checking it, everything looks good. I bled the brakes just now to be sure that wasn't the issue and I got no air out of that line.

I replaced that wheel cylinder a few months ago, but it's not leaking. Is it possible that it's not working? Has anyone ever had that problem?

Since the other rear brake is working just fine, the only other thing I can think of is the line being clogged between the 'T' and the wheel cylinder, but that seems unlikely. I just bled the line and there certainly seemed to be plenty of fluid coming out.

I also failed emissions at idle. They said it's running too rich so I'm assuming I need to readjust the carb or something. I suck at this stuff, but I've got an edlebrock 1405, so I'll use some google-fu and see if I can't find any info on it.
Any other suggestions on cleaning up my emissions?

I've attached both reports below.

 

[Stomis]

I say test the brakes for yourself. You could have an oil impregnated brake shoe from the older leaky cylinder. Ive seen them look totally fine and slip like a mother ****er.

 

[ashman]

I say test the brakes for yourself. You could have an oil impregnated brake shoe from the older leaky cylinder. Ive seen them look totally fine and slip like a mother ****er.

hmmm, ok, I'll look at the shoe. I thought it was dry, but don't remeomber look at that.

 

[K5dreamer]

I have never seen that brake report in my life... and I worked at several shops... I have no idea how to interpret that for you

shooting from the hip it seems like you're biasing to the driver side both front and rear, just worse in the rear. Have you popped the master cylinder open to see whats going on up there? may also be a proportioning valve issue? if you have adequate flow, (you said lots of fluid at bleeding), then it may be a pressure issue, which would stem from further up the line.

for the High CO%, it actually sounds like not enough air, more than too much fuel, when did you last change your air filter? are there any rats nests or blockages in the intake passages?

 

[ashman]

I'm still baffled on the brake issue. The most obvious answer would be that brake just way out of adjustment, but it's not. MC is new and the prop valve does front to back, not side to side biasing, so I can't see how that would be an issue. It's got to be something stupid simple so tomorrow I'm going to take the whole brake assembly apart and put it back together. Maybe I just did something stupid when I put it together last time.

On the emissions, I thought not enough air too, so I changed the air filter, but it didn't help. Gonna try adjusting the carb and see what that gets me.

 

[Fordum]

Several years back, I could have told you what was wrong with that one brake. Had it happen to me a couple of times.
Modern drum brakes are self actuating, which means that the whole brake assembly rotates when the shoes touch and cause the rotation of the drum to help jam them in tighter.
Thus you use the force you are trying to stop to help you do it.

But, back in the day, you had forward and rear shoes. One had full friction material and did most of the stopping.
The other did not have as much and only helped actuate the main shoe.

If you got them wrong, you did not have good brakes on that side.

Most of the time, you put the forward shoe on the back and vice versa. That gave you very poor braking.

But sometimes you would put both rear shoes on one side and both front shoes on the other.

That got you one wheel that stopped very good, and one that did not stop at all.

Nowadays, both shoes are the same, but even so, make sure that the shoe assembly is free to rotate slightly around the wheel cylinder.

A Very Small amount of antiseize or heavy lube where the edges of the shoes scrub on the backing plate helps.

 

[ashman]

thanks fordum, I'll check that out. as I recall, the front and back shoes are different sizes so I'll check to make sure I have them on correctly.

 

[4xcrazy]

I've never,,,,,ever,,, had "slippery" brake from oil soaked shoes. Whenever I have ever had a wheel cylinder, or axle seal leak and soak the shoes, they always grab really hard and tend to want to lock up real easy.

I have also had a situation, where I lost the rear brake power, coming down a decent sized hill on an off road trip, kind of sucked, but I made it down.

I replaced the master cylinder, I was SURE, that was the problem, from previous experiences in life but after replacement, the rears still didn't work.

So I started at the wheels and worked my way towards the front, cracking the lines, then having someone press the brake pedal, noting any pressure, nothing at the wheel cylinders, I don't remember exactly what it was, but after I cracked open the lines at the t-fitting over the rear diff, whatever was going on, cleared out. Something was blocking the flow.

It opened up and I have never had any problems since.

As far as the emissions, I'm out dude, I gave up on carbs a LONG time ago

 

[Stomis]

Several years back, I could have told you what was wrong with that one brake. Had it happen to me a couple of times.
Modern drum brakes are self actuating, which means that the whole brake assembly rotates when the shoes touch and cause the rotation of the drum to help jam them in tighter.
Thus you use the force you are trying to stop to help you do it.

But, back in the day, you had forward and rear shoes. One had full friction material and did most of the stopping.
The other did not have as much and only helped actuate the main shoe.

If you got them wrong, you did not have good brakes on that side.

Most of the time, you put the forward shoe on the back and vice versa. That gave you very poor braking.

But sometimes you would put both rear shoes on one side and both front shoes on the other.

That got you one wheel that stopped very good, and one that did not stop at all.

Nowadays, both shoes are the same, but even so, make sure that the shoe assembly is free to rotate slightly around the wheel cylinder.

A Very Small amount of antiseize or heavy lube where the edges of the shoes scrub on the backing plate helps.

The floating design drums are most definitely still a short and long shoe. As you said the short shoe always goes forward.

I know Lauras new car has fixed rear drums and so did my old beater and that thing had equal sized shoes.

I still say you've got a soaked shoe. For the $20 brake shoes cost for one of these trucks just change them again, bet you'll be surprised. And you could pass emissions if you just yank the air cleaner out for the test. It will drop your numbers like 200.

 

[Deuling]

Turn the air fuel mixture screws all the way in and bring em out about 2-2.5 turns. Then start it and slowly turn one in untill it stumbles and then turn it back till it stops. Do the same with the other. That should get you in the ball park for fuel air mixture. Could be jets though too.

 

[Comatose Camel]

As for emissions, try adding a bottle of that guaranteed to pass stuff.

 

[diesel4me]

Several ways to cheat to pass emissions tests...one popular one is to add a few bottles of isopropanol dry gas to a 1/4 tank of gas and get it good and hot before the test by driving it at highway speeds several miles --often vehicles that would pass easily flunk because your forced to sit and wait so long in the line waiting to get the test more than any other reason.....advancing the timing also can help,the carb idle mixture should be adjusted "lean" as possible without making it idle lopey,and in extreme cases pulling the PVC valve out of the valve cover sometimes help lower emissions if it has blowby,but only leave it out during the test............................................................................................................................................................................................................As for the brakes,its very possible to have a wheel cylinder seize up tight and not apply pressure to the shoes,though that should create a dragging brake situation if it does decide to extend as ir should,it usually wont retract...I've seen brake lines rust up on the inside and cause a partial blockage before also--one dent in the line or a kink can do the same too...

 

[ashman]

thanks for all the replies guys. At least now I've got a few things to try.

Diesel4me, now that you mention it, I do remember a few months back having what felt like a brake lock up and drag then there was a loud pop or crack noise and everything seemed ok when I checked it out. I assumed a small rock got caught in the drum and either got crushed or spit out, but maybe it was the wheel cylinder.

On the emissions: It's not failing bad, so I'm sure a few of the cheats would work, but since I've never had problems before, I'm assuming it's indicating something isn't running as well as it should, so I'd like to fix it if I can.
One issue I have that may be somewhat related is the engine tends to ping at higher rpms if I give it much of the skinny pedal. I've always heard that was from running too low of octane gas, but since it's a 383 with higher compression, I already run the high octane stuff anyway. Is this issue related? Even if not, how do I fix it?

 

[K5dreamer]

On the emissions: It's not failing bad, so I'm sure a few of the cheats would work, but since I've never had problems before, I'm assuming it's indicating something isn't running as well as it should, so I'd like to fix it if I can.

as a tree hugging hippy.... i salute you

And I missed the fact that this was an aftermarket build on an engine. a high compression 383 you say??? have you played around with spark plug temperature ranges and different gap sizes to see what runs best? Or did you just stick with the factory part number for the plugs?

http://www.summitracing.com/experta...lugs-101-Understanding-Spark-Plug-Heat-Range/

 

[ashman]

just factory specs on the plugs. I've been wondering if I need a hotter spark...

 

[K5dreamer]

just factory specs on the plugs. I've been wondering if I need a hotter spark...

actually, you probably need cooler spark plugs. especially if you're getting pinging (pre ignition / detonation) under load at high rpm. The higher compression would raise combustion temperature, you want cooler plugs that will dissipate heat into the cylinder head faster.

at least thats my limited understanding of the issue, Im sure more experienced engine builders (IE those who have actually built an engine or two) will chime in to correct me if im off target.

 

[Stomis]

Or pull a couple points of total timing. Or if its only doing it in a certain range and then straightening its self back out change the curve to come in a little later.

 

[ashman]

Or pull a couple points of total timing. Or if its only doing it in a certain range and then straightening its self back out change the curve to come in a little later.

I'm going to check the timing when I get some time, but I don't have any experience with adjusting the curve at all. I have stock HEI. Is there an info page that I could read up on?

 

[ashman]

I still say you've got a soaked shoe. For the $20 brake shoes cost for one of these trucks just change them again, bet you'll be surprised.

you may have a point. I pulled the brakes on both sides and they do look different. the set on the left is the possibly soaked shoes. New ones should be in tomorrow.

 

[Stomis]

I'm going to check the timing when I get some time, but I don't have any experience with adjusting the curve at all. I have stock HEI. Is there an info page that I could read up on?

I dont think you can adjust the vacuum timing curve with the stock dizzy. Although you saying that raises another red flag. You've got a high comp 383 that you spin. Time for an MSD setup dude! Weak spark alone could be causing your issues.

Cough up the coin for a pro billet and a box if you can but if you're on more of a budget get a streetfire coil on cap dizzy and run it off a 6AL. Gap the plugs to .045 and you'll get a way better burn. I bet the pinging goes away without changing anything.


And by the way glad you hopefully found a simple solution for the brakes.