Bogging/stalling when braking

[caddyhack]

Have you tried swapping another carb onto the truck?

[thelawdoc]

Caddyhack, not yet. I have to decide between AutoZones' Autoline C935 which is my precise carb, or a mono jet that was suggested to me.

[blown240]

Some of those mounts are Urethane. Thats why they are expensive. They are nice, but REALLY pricey. Rubber if fine.

[thelawdoc]

Blown, yeah, I ordered 2 from Parts Geek. Like $20. I have a floor jack. Do you think I can change them myself? I mean it looks easy enough, but I am finding out that nothing is simple when it comes to these trucks.

[blown240]

I don't think they are that hard to change, but someone else who knows more than me should chime in on that one....

[TJ's Chevy]

In my experience with monojets they seem to outlast a rebuilt model b....I have an 84 with a 292 and I went to autozone and told them the year and got one...price I don't remember anymore. Now you say that you started having stalling issues AFTER the tranny was rebuilt?

[thelawdoc]

TJ, in recollecting everything I did since the truck ran right, the tranny job was first, then the tune-up. I did not notice the stalling issue after the tranny job, but then I only drove her a few days, then parked her for a month or so, before starting the tune up. Then the stalling issue which has now gone on for weeks.

[ls60apache]

Originally Posted by thelawdoc

Guys,
I do not know of any hills here in Brooklyn. I know the truck will not stall in neutral on a level street. That is what I do at the lights and stop signs as I go from point A to point B. I do not see why a hill would matter. But I think I will just bring her back to the tranny shop and see what they say about it. If I replace the carb and the stall remains, then I would be sure that there is some tranny problem. There are simply no other suspects.

so your saying you put the trans in neutral as you coast to a stop light or sign and it still stalls?? getting the truck moving on a hill and then stopping in neutral was just to see if the actual motion of stopping was making it stall. that would have eliminated anything in the drivetrain. it is quite possible that something in the power glide torque converter can be making it stall. does it sputters and stumble to a stall like fuel or vacuum issue or does it stall like you turn off the switch or does it stall like a manual shift without disengaging clutch?? {think this was mentioned before }

[thelawdoc]

Apache, she does not stall if I put her in neutral before braking. She only stalls if I give a hard brake in D or R. If I give soft brake, I can even get away with needing neutral. She used to stall with bogging. After I changed out my balancer and did timing, she stalls with virtually no bogging/stuttering. Plus, I just found out yesterday that my driver side engine mount is busted, though I do not see that being the cause of the stall.

[blown240]

I personally think it really boils down to this:

1. Fix the mount - you already ordered it
2. Take it back to the tranny shop - Should be free
3. Throw a carb at it - $$$

if that doesn't fix it, then I have no suggestions...

[thelawdoc]

Blown, that is exactly my plan.

[TJ's Chevy]

I work on chainsaw and timmer carbs daily...sometimes a carb can only be rebuilt so much before its just plain done...On a regular basis we're changing out carbs on saws because you can't see those passage ways that can still be clogged....and because of the dusty conditions.

[thelawdoc]

TJ, yes, I understand that a part can just become worn out. I understand that a carb has some intricate parts. And my carb has been declared worn out by a couple mechanics. But I do not understand one who says a part is just worn out without being able to say where or how it is just worn out. If a simple carb such as the Rochester B is just worn out, my mic and caliper should reveal where/how it is worn out, no? As for the passageways, my method of servicing them entails the use of carb cleaner/brake cleaner and air sent in with the straw. I seriously doubt any clog can remain in there after I have been to it. Plus, I think a clog would reveal itself in the starting, idle, or running. I am a novice, wannabe mechanic, but I still believe in my carb because I cleaned it and I examined it, and then two other real mechanics checked my work and could find no issue. And it also seems to me that, in this information age, if the Roch B design was such that it could be worn out without giving even the slightest physical evidence for the fact, we would be hearing about it from hundreds of guys. There are a gazillion Roch B's out there. But we tend to hear only about its warping (I do not have warping), and it being prone to leakage (I have no leakage); and it being prone, like many carbs, to tiny grit (my carb is squeaky clean). I have not heard of this carb being rebuilt properly and then checked by two or three guys, and then being bad without anyone being able to say what, exactly, is making it bad. I am not saying it is a physical impossibility that there be an indiscernible defect in it. But I do believe it to be highly unlikely and not a proper basis to trash this carb. I am more inclined to suspect a tranny issue, since I have confidently ruled out any ignition issue. And I do have that busted engine mount, which is easy and cheap to change out and just might be the cause of my oddball stall. (It makes sense to me that, on a hard braking, the engine moves in some fashion as to irritate something in the tranny, which in turn stalls her out.) Of course, if it be the carb in the end, I will feel like an idiot and be kicking myself for a long time. This story has cost me a lot of money now, both in consultations with mechanics and in loss of use of the vehicle. A lot of money. Hundreds of dollars. And it has stressed me out. But I will get to the bottom of this, one way or another.

[chevy_mike]

My money is on a trans issue. If you can put it in neutral and have no issues, you ARE using vacuum, no different than if in drive. If it only stalls when in drive or reverse and hit the brakes hard, the problem is in the trans.

If it runs great with the current carb setup, outside of this issue (i.e. you can drive, stomp on the gas, etc.), and the carb is doing its job, it's not the issue. A carb problem you will see ALL the time, not just hitting the brakes.

My guess is something is not releasing quick enough in the trans when you stomp on the brakes but when you ease on the brakes, it allows whatever the problem is to release, since it is doing it slowly.

[ls60apache]

motor mount wont cause anything internal with trans but may cause some binding on the throttle linkage.. im kinda betting something goofy with torque convertor.

[Jimal]

Originally Posted by ls60apache

motor mount wont cause anything internal with trans but may cause some binding on the throttle linkage.. im kinda betting something goofy with torque convertor.

I can't think of any scenario where the torque converter could do something like what is being described. There is no mechanical connection between the engine and the transmission, and the torque converter requires RPM to stall and transmit power to the input shaft. Same with the transmission. If the truck moves and shifts the transmission is fine.

[tenni126]

I suppose it would be worth making sure the transmission linkage itself isn't interfering with anything when it's rotated into gear. Maybe the arm is hitting something that's clear in neutral? That's kind of a long shot, though. I'm pretty sure the modulator valve is on the passenger side, opposite the linkage, so I dunno what would hit. Just spitballing.

[blown240]

Any updates on this? Im hoping you got it figured out...

[Jimal]

I'm assuming we'll hears something now that the holidays are more or less over.

[thelawdoc]

Guys, well I wanted to drop the truck at the tranny shop before Christmas, but the guy there said he would not get to it until after the new year -if I wanted him to check it out, which I did. So I also went away. So there is no news at all for the moment. Sorry I did not indicate this situation to the many guys here who have been helping me out. But seems like this week should bring the final episode in this ordeal.

[Monte's62]

Man the suspense is killing me, this is like watching a season of "breaking bad" or "dexter". I keep checking in every day to see if anything has happened. Sounds like you have some good help and ideas. Good luck.

[Jimal]

What's the latest on this? WE DEMAND ANSWERS!!!

[thelawdoc]

Guys,
Yes. Me too. I dropped the truck off at the tyranny shop on Tuesday. He is supposed to call me. My guess is they are stumped.

[Jimal]

Originally Posted by thelawdoc

Guys,
Yes. Me too. I dropped the truck off at the tyranny shop on Tuesday. He is supposed to call me. My guess is they are stumped.

If the tranny shop is stumped, either it isn't the tranny or you need a new tranny shop. This isn't a 4L60-E we're talking about here. A Powerglide is about as stone simple as an automatic transmission can be.

And my money is still on the carburetor.

[blown240]

You changed the motor mount that was broken?