Agreed, and your efforts to make the car something she would want to drive too won't go unnoticed by her!
Brake experiment
- Thread starter rkrochen
- Start date
rkrochen
Senior Member
You may be right I just need to think about it. Anyone else wish to jump in please do so.
Triple Pickle
Senior Member
I stumbled upon this effect accidentally at a young age by putting any junkyard MC that would fit and work on different cars.
Smaller bore is equivalent to increasing the length of the stick in a simple lever. Longer stick, less effort but longer push on the stick to do the same work.
Larger bore is a shorter stick. More effort, shorter push to do the same work.
That's my understanding of it.
Larger bore is a shorter stick. More effort, shorter push to do the same work.
That's my understanding of it.
Smaller would give more travel, but it will increase pressure.
High school physics with a touch of night school hydraulics course...
Triple Pickle
Senior Member
I think the larger bore would make it less touchy if it were manual brakes. But with the power booster doing the lions share of the work I don’t think you’ll notice much difference in effort. Just my thoughts. It can get tricky.
Triple Pickle
Senior Member
I agree but, what would achieve the desired effect? Bigger would put out more volume and with the booster doing the work it might be more touchy. Like I said it’s tricky sometimes. Not saying you’re not right but, I wouldn’t count on it.
thethee
Senior Member
With a larger bore and the same pedal travel you would move around more brake fluid right? Would that not increase touchyness?
Triple Pickle
Senior Member
I would think so. The booster is the wild card here. It might have enough power overcome whatever work you can give it.
I know a little about hydraulics. Here’s some pics taken minutes ago at my industrial maintenance job! I troubleshoot this stuff all the time. Again, I’m no expert. But I have seen the so called experts get confused!
commando1
Old Man with a Hat
Please don't even think about this any further. Each piece was designed to work perfectly in the overall design. Try changing the master cylinder. You have conquered the near impossible, getting all four to lock up at the same time.
I have to agree - we're all overthinking it.
Checking the shoes (drums) for contamination is a quick first.
Upgrade to dual circuit master as you noted you are planning is a good 2nd step.
Checking the shoes (drums) for contamination is a quick first.
Upgrade to dual circuit master as you noted you are planning is a good 2nd step.
rkrochen
Senior Member
Getting everything to work properly is not the issue it comes with years (actually decades)of experience being a mechanic. I like the idea of changing master cylinders and will do so but it raises other questions. I have been out of touch the last couple of years due to medical issues and just need to get my brain back into working condition.
rkrochen
Senior Member
No problems with the shoes they are like new. Adjustment is perfect and pedal stroke is good as well. It’s just the way the system was designed.
Triple Pickle
Senior Member
The dual circuit upgrade might change the characteristics if the booster is also replaced even if the bore is the same.
rkrochen
Senior Member
I was thinking the same thing. Has anyone noticed changes with their dual cylinder upgrade.
Here's your answer, as per Sir Richard Ehrenberg, SAE, Mopar Action, etc. Note that this is for the wheel cylinders, which means that a larger master diameter would make for a similar hydraulic situation. I used these reduced-diameter wheel cylinders when I rebuilt my rears, but I'd be leery of experimenting with cylinder sizes otherwise. [ [I know this is for a disc/drum car, not powered drums as per this thread, but you get the idea.]]
rkrochen
Senior Member
Good information. This creates the same effect as changing the master cylinder. My thoughts are to do the MC upgrade and see what happens. I can then look into these cylinders if I am still having issues.
Clover
Well-Known Member
My two cents: my primary suspect is the booster. When I got my ‘72 Imp, it had super-touchy brakes. I put new cylinders and shoes in the rear, with no change. I drove it for a few years and got used to the touchy brakes and basically forgot about it. One day, my booster outright failed to boost. Pretty scary, trying to stop that behemoth with no boost! Anyway, I put a reman booster on it (back when you could still get them) and they have worked perfectly, since. No touchiness at all. It was the booster, all along.
I'd say that if the car is locking the brakes evenly etc., that I would leave the hydraulics alone.
As @Clover and @FURYGT have mentioned, the answer may be in the booster.
I'm not really familiar with the internals of the booster, so I can't say that a new/rebuilt booster is the answer. Actually I even wonder if the replacements mentioned weren't working as well as they should and that increased the pedal effort.
I am wondering if there is a slick and easy way to reduce the amount the booster.... Ummm... Boosts... Limiting vacuum or something like that... Just thinking out loud and glad I didn't have to start drawing stick figures on teeter-totters to explain the hydraulic mechanical advantage.
As @Clover and @FURYGT have mentioned, the answer may be in the booster.
I'm not really familiar with the internals of the booster, so I can't say that a new/rebuilt booster is the answer. Actually I even wonder if the replacements mentioned weren't working as well as they should and that increased the pedal effort.
I am wondering if there is a slick and easy way to reduce the amount the booster.... Ummm... Boosts... Limiting vacuum or something like that... Just thinking out loud and glad I didn't have to start drawing stick figures on teeter-totters to explain the hydraulic mechanical advantage.
Triple Pickle
Senior Member
It might actually have the wrong master cylinder on it too.
Like I said before, the booster is the wild card here I believe. It might have enough power to make small changes in bore sizes act differently than we might normally think. With manual brakes, if you change the size of any bore in the system you will definitely notice a big difference. With the booster doing the work it will be different but I’m not sure if it will give you the feel you’re looking for.
Like I said before, the booster is the wild card here I believe. It might have enough power to make small changes in bore sizes act differently than we might normally think. With manual brakes, if you change the size of any bore in the system you will definitely notice a big difference. With the booster doing the work it will be different but I’m not sure if it will give you the feel you’re looking for.
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