Baer's won't lock up

[ss dave]

I have Baers Serious Street system front and rear, their supplied Master cylinder and my 11" booster on my 69 and I cannot get them to lock up. They will stop.....OK, but I would like to have the ability to lock them up. What is the problem? Thanks.

[astroracer]

Why do you want them to lock up? If they stop the car now without locking up that is a very good thing because YOU still have control of the car. When the brakes lock up that is a loss of control and that is not a good thing. I would say, if the brakes are working correctly, stopping the car well and are not locking up then you have a good system...
If I am wrong here please clue me in as to why...
Mark

[Jagarang]

If they don't lock up on wet pavement you may have an issue. This would seem to mean that they are not working correctly. If however you can't lock them up on clean dry pavement, I would agree with Mark and say your probably good to go. See if you can get a 60 to zero stopping distance, this way you can compare your performance to available data. One way you can get this, I think, is with these G-Tech Pro and similar performance modules.

[CAMAROBOY69]

I am interrested in this information also. Seems like if they were working real well (like hydraboost) then you should be able to lock them up with no problem. I know its not the optimum for braking performance and control but after spending all that money it seems like they should lock up on dry pavement. (Watch the hydraboost vids, those cars lock right up) :)

[CAMAROBOY69]

Even better answer. Did you contact Baer and ask them? If anyone would know, I am sure they would.

[ss dave]

First of all I agree with Mark also. The stop is smooth and almost feels like an ABS system, which is good. However, my thinking is: that with them not locking up, I feel I'm not getting the most out of them. Kevin, I would like to know where the "available data" is so I can compare, that would be ideal. Secondly, I have a Hurst Line lock and with the front brakes not locking up I can't get the most out of this system, the car "pushes" thru the line lock-I would like a good solid lock up. I think I'm making enough vacuum with the booster, could I need a larger bore size in the MC? What do you think, any experience with this?

[ss dave]

Adam, I did talk with a Baer tech and he said it could be I'm not making enough vacuum, but the booster is new and seems to work properly, I'll give them another ring but there is so much experience on this site I thought it worth while to post the question and see if anyone else had an idea.

[CAMAROBOY69]

So basically the answer is that they should be locking up right??

[ss dave]

Yea, the tech stated they should lock up. My mechanic mentioned he had a similar problem with another car and changed the bore size and that solved it. I would like just one good burn-out for the pics! lol

[USAZR1]

You need a smaller bore m/c. Remove the Baer unit and replace it with a mid 70's Corvette m/c. End of problem.
Been there,done that.

[Hydratech®]

It's about having the available power to be able to do so, which then allows for the largest amounts of actual braking called "thresh hold braking". Locking the wheels up actually makes the stopping distances WAY longer, and what we are attempting to illustrate in our vids is the ability to do such. IF you can get the brake system dialed in and balanced correctly, it is all about being able to ride the absolute ragged edge of lock up = thresh hold braking....

Which also happens to be exactly what ABS systems help to provide in modern ultra high performance cars...

BTW - USA ZR1: The installation of a larger bore mc will most definitely require even more pedal pressure to accomplish the same stop = will only make the condition worse!

[andrewb70]

BTW - USA ZR1: The installation of a larger bore mc will most definitely require even more pedal pressure to accomplish the same stop = will only make the condition worse!

How true indeed!

Andrew

[USAZR1]

Sorry for the brain fart,guys. You're definitely correct.
Must quit daydreaming. :sleeping:

[CarlC]

If the front brakes cannot be locked in dry conditions, how can you know for sure if the full braking system capabbility is being used? A 5' shorter braking distance may save the front end of your car.

Threshold braking points can be tuned with the MC. Having too small of an MC can cause just as many problems as too big. Too light a pedal effort is very difficult to modulate and can easily lead to lockup, which is no fun under any condition.

[David Pozzi]

I'm having the same problem with my wife's 73 camaro, Baer Track system and 11" booster with Baer 15/16" master cyl bore. Can only lock the wheels with extreme pedal pressure, the system should be able to come very near the point of lockup with repeatability, ours takes way too much effort right now, my wife can't begin to lock a wheel, so can't come close to max braking levels.

My plans are to check vac level and try a smaller bore master cyl.

[ss dave]

Just as I hoped, alot of experience, thanks for the input. So it sounds that if I want my brakes to lock then get a smaller bore size MC. Any suggestions as to a MC that would work? A 70's corvette MC perhaps? any others? I believe the bore sizes differ by as small as an 1/16th" and that even that little of a change will make a difference. Thanks

[CoryM]

Smaller MC bore will make it easier to apply more force on the caliper pistons (simple hydraulic theory) BUT it will also require more pedal travel to do so. I am assuming the pedal is nice and hard/high now but you just cant push hard enough to lock it up?

Find out how much engine vacuum you have at idle. I had 9" in my camaro and I would get assisted braking under normal applications, but when you stomped it you lost assist. Very hard to drive like that. A vacuum canister would fix that though.
Shut the car off, pump the brake pedal a few times. It should get harder. Hold the brake pedal down and start the car. The pedal should sink further. If not, your booster isnt doing much so make sure you have vacuum going to it and that its not leaking.

[David Pozzi]

I have two master cyls for early 70's ford cars, one 7/8" and one 13/16". The ports are on the engine side and the bolt holes had to be filed a little to fit the GM spacing, they both have deep holes in the rear for manual use, would require the long booster pushrod or a spacer in the hole. I tried these without the booster on the same car first, then put the booster on it. These have adequate travel, there is a (Monza?) master cyl that has a 7/8" bore but it's reservoir is small and it has much less stroke which was bad for a manual use. It might work OK for a power system, the ports are on the fender side.
David

[fuzzyonion]

Monza used 3/4" bore and the stroke is very short. Maybe too short. Stroke is the same whether manual or power. It feels like less stroke for power because the pedal lever ratio is shorter, and sometimes because the bore is larger, but volume displacement to move the caliper pistons must be maintained.

79 Malibu used a manual brake master cylinder of 7/8" bore. This might be a fair alternative provided the caliper pistons dont have excess retraction. It should have enough volume for systems using front dual caliper pistons of 45mm or less diameter, and rear single of ~same diameter, or rear drum.
The ports are on fender side, and the ports are the same threads as the older cars, 1/2" and 9/16", but the ports are reversed (rear port to front brakes). It has a plastic resivoir but is not a QTU.

45mm dual piston clampers have the same area as the original 2.5" diameter single pots for that master. That Malibu had the same manual pedal ratio as the 70+ Camaro.

[harshman]

ll throw some fuel to the fire: Hydroboost will dead nuts solve your problem. I had the same problem when I went to Cal speedway for the PHR shoot. My brand new vac. pod couldn't stop my car at all. I strapped a Hydratech unit on and proceeded remove my face from my windshield.

[427v8]

What you really need to know is your brake line pressure. If you can get 1200 psi then your caliper pistons are too small. If you can't get 1200 psi, you MC is too big ( or you booster isn't boosting enough )

More than 1200psi and you have too much pressure and are beyond the rated pressure of most brake systems.