Trying to figure out if I have a brake problem...

[ITR#231]

When I first drove my 88 CRX Si, it wouldn't stop for sh*t and it couldn't even lock up the bald, hard street tires it came with. I had never driven a CRX before so I really didn't have a frame of reference, but it didn't feel like it was stopping like it should.
Since then I have completely flushed the fluid with DOT 3 fluid (the fluid I got out was cola colored and very slightly milky) to the point that every corner of the car bleeds clear fluid and no bubbles. I have two cans of ATE super blue waiting for use, but I don't want to waste it on frequent flushes while I'm sorting everything else out. I have also replaced the rotors with fresh Brembro blanks, and I replaced the pads with PF carbon metalic pads. Again, I have a set of Carbotech XPs waiting for use, but since these don't stop well cold they won't help me decide if the system is working. As for the rest of the system, it looks grossly functional with no obvious damage. The pedal feels pretty good but a little soft. I have done nothing to adjust the rear drums, but I have a set of OEM shoes ready for the rears and after install and adjustment things might feel a little better.
I have tested the car at a number of autocross events before it sees any track time to help uncover any other safety issues before I'm moving very fast. The brakes stop the car but still can't lock up a set of 185/60/14 victoracers, and I'm 90% sure that something still isn't functioning properly. The problem is, my reference autocross car is a 98 ITR which generates amazing braking force, so I'm not sure what I should expect from the CRX. So, I'm posting this here since I figure that most of the CRX Si's on this board have their brakes working "at the top of their game" and can tell me what I should expect.
What are some benchmarks I can use to determine if this car is braking properly? What things can I look for as far as the master cylinder, brake booster, etc. to make sure they're functioning properly. What other maintenance procedures (other than getting to the rear drums) can I do that might help? Thanks for any info. Sorry for the long question.

[il8apex]

Funny, when I first drove my '89 I thought that I was going to die at every intersection. I replaced the M/C, did the rear disc swap, and have new pads/rotors all the way around. It's much better now. I think the culprit was old fluid, a poor seal on the old M/C, and glazed pads.

It's not scary any more, but still takes more pedal effort than I'm used to.

Anyone else out there?

-Tom

[B Breon]

Having the rear drums adjusted properly makes a big difference! Also, have you pulled the back drums and looked at the cylinders. I have had a leaking cylinder that I didn't know until I pulled the rear drum. Replacing the cylinder and adjusting the shoes up made a world of difference. If you still have the emergency brake, it should only take 2-3 clicks to work. This is how you know you have the rears adjusted properly.

If you still are having problems after the rear rebuild and adjustment, I would test the mastercylinder and booster as recommended by the service manual.

If I remember correctly you do the following: With the car running pump the brakes 4-5 times and hold. Turn the car off, if the pedal drops, the booster is working. With the car off, pump the breaks 4-5 times and hold. If the pedal drops, the mastercylinder has a leak or you have a leak somewhere in the system.


Victoracers have good grip and a high moment of inertia (heavy). If you have heavy stock rims with the victoracers on them, under autocross conditions you may not be able to lock things up uless you do something crazy to upset the car because of the rolling momemtum of the tires/wheels and the grip. What type of surface are you on, sealed or old asphalt or concrete? Typically I have rarely locked up victoracers on the race track, the only time being at the end of the long straight aways (110MPH) and an OH SHIT! put your leg through the firewall gotta stop the car before I kill myself braking situation.

[ITR#231]

Thanks for the input, guys.

il8apex,
Did you replace the MC with a new one? I was hoping to pick one up from a junk yard or some place similar, but naturally I don't want to buy one with the same problems as my current MC. Also, I notice that you swapped your rear dics. Did the 89 have rear drums? I kind of want to keep mine, since they're lighter and have less rolling resistance. I should be able to get the car to stop the way I want it without having to swap the drums out.

B Breon,

Yes, it's becomming clear that I need to get on top of the rear drums sooner than later. You're also not the first person to warn me about the rear cylinders which I have to admit I haven't checked. Will a leak be obvious, or is that something I should plan to replace even if it looks good? Also, to test the booster, I was told to pump the brake with the car OFF and then start it to see if the pedal drops. Does that sound right, or do you do it the other way?
Your point about the victoracers is well taken, and that's why I included that info in the first post. I still think I should be able to lock them up on old asphalt. Occasionally I run on brushed concrete sections and I wouldn't be surprised if they never lock up there.

Thanks again for the help.

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'88 CRX Si - ITA/PS2 road racer: Handles like it's on jack stands
'98 ITR #0231 - DS autocrosser: Handles like I sold it
'02 Jeep Grand Cherokee - daily driver/tow vehicle: Handles like a jumping castle

[Davidov]

You may be able to add a master cylinder from a Honda about the same size as your CRX, but from a car with 4-wheel discs.

If you can find one that will bolt up to your brake booster, see if the MC has a larger bore than your CRX does now.
This will give more effort to the brakes, and a higher pedal.
Look into some stainless steel braided brake lines also. They are about $100 for a set for your car.

[greg_umbay]

Originally posted by B Breon:
If I remember correctly you do the following: With the car running pump the brakes 4-5 times and hold. Turn the car off, if the pedal drops, the booster is working. With the car off, pump the breaks 4-5 times and hold. If the pedal drops, the mastercylinder has a leak or you have a leak somewhere in the system.


I think its just the opposite, keep pumping the brake pedal and if it goes hard, the brake booster is good.

The rear drum adjustment makes a big difference.

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http://www.ita.hondapowered.com

[B Breon]

Davidov makes a good point about the SS brake lines. They do help.

When you remove the rear drum, trust me, you'll know if you have a leak. There will be fluid and all the brake dust will be gooo!

You are right, you do pump with the car off and then turn it on, had that backwards.

Alternative master cylinders. You can get the 90-91 from Advanced Auto (Parts America) rebuilt for $45 plus core. THe 90-91 is a 7/8" bore. An 88-89 is a 13/16" bore. This is a legal change for IT.

Now, you can also put in a 91 Civic EX master cylinder from a Non-ABS car. This will bolt in and is a 15/16" bore. This is not ITA legal, though

But, remember, a larger master cylinder will give you a higher pedal but requires more foot pressure to actuate.

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Brent Breon
Cendiv ITA #26
www.360racing.com (http://www.360racing.com)

[This message has been edited by B Breon (edited November 22, 2002).]

[ITR#231]

Yes, the SS lines are on my "to do" list. I was going to hold off on them until I got this all sorted out, but now it's looking like the old lines may actually be contributing to the problem.

As for the MC, good info about Advanced Auto. I have been looking for sources for rebuilt units (for several parts) that only require a core deposit and a little cash. Is the 90-91 7/8" bore MC considered an upgrade compared to my 88 13/16"? It's not normally something I would bother with, but if mine needs replacing I guess that would be a good time. What's required to fit the 90-91 MC to my 88?
As for the other MCs, I'll be keeping this car IT legal.
With respect to the "higher pedal" and "more foot pressure," what exactly does this translate into? Is it actually more force to move the pedal down, or do you simply have to push the pedal down farther? It's hard to say if I like the braking feel of my 88 since I'm not convinced that it feels like it's supposed to anyway.

Thanks!

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'88 CRX Si - ITA/PS2 road racer: Handles like it's on jack stands
'98 ITR #0231 - DS autocrosser: Handles like I sold it
'02 Jeep Grand Cherokee - daily driver/tow vehicle: Handles like a jumping castle

[B Breon]

Nothing should be required to install a 90-91 in place of an 88. They are direct replacements. But, if you go to rear discs from a 90-91 in the future, make sure you get the 90-91 prop valve.

With a bigger mastercylinder, you displace the same fluid with less stroke, so the pedal will stop at a higher point. But, with a bigger piston in the MC, you lose some mechanical advantage and it requires a little more pedal force. There is a great article about this on the net. I'll see if I can find it again.

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Brent Breon
Cendiv ITA #26
www.360racing.com

[Knestis]

<font face="Verdana, Arial" size="2">... You can get the 90-91 from Advanced Auto (Parts America) rebuilt for $45 plus core. THe 90-91 is a 7/8" bore. An 88-89 is a 13/16" bore. This is a legal change for IT.</font>

Hi, again. The "induction system" is given as a specific example of "complete assembly" of a "component" in the ITCS. My understanding (based on a semi-official interpretation with the ITS RX7) is that the entire brake system may be up- or back-dated but not parts thereof.

Trying to maintain the line between NERD and PITA but this is the identical question to that posed in the strand about the cam. Are all of the rest of the parts identical for the systems with the 7/8" and 13/16" M/C diameters?

Kirk

[ITR#231]

Knestis,

You become a PITA when you start making these comments out of context to what is being asked. In this case, if I'm replacing my MC and there is a rules issue with updating the MC alone, that is a very helpful comment so you won't hear any complaining from me.

To answer your question, there are many differences between the braking systems between CRX years, from MCs to calipers to rear discs to prop valves and more. I have a small supply of nice brake pads that only fit the 88, so I don't want to change calipers, and I want to keep my rear drums as well. That means I must keep my 88 MC (or replace it with an 88 MC) and again, that's useful information.

B Breon,

I'll see if I can dig up that article, but I think my physics is good enough to understand how piston sizes and displacement will change pedal feel. And, my gut reaction is that I would actually prefer a longer pedal with less effort, mainly because it makes the pedal less of an on/off switch in tense situations and it's easier to modulate the brakes (my opinion, naturally). However, it appears to be a non-issue if I have to stick with the 88 MC.

First I must find out what my problem is. Then I'll check the rule book to see what's part of the "system" that must be swapped completely.

Thanks for the help, guys.

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'88 CRX Si - ITA/PS2 road racer: Handles like it's on jack stands
'98 ITR #0231 - DS autocrosser: Handles like I sold it
'02 Jeep Grand Cherokee - daily driver/tow vehicle: Handles like a jumping castle

[Greg Gauper]

FYI - A longer pedal travel is NOT easier to modulate. A perfect brake system with no travel is the easiest to modulate! The human body can regulate with force feedback much easier than displacement feedback.

Sit in a modern formula car or sports racer and check out the brake pedal. To an IT car it feels like you're stepping on a piece of solid frame!

BTW, some of the more modern industrial control systems us joysticks with built-in force transducers instead of lever operated potentiometers for their operator control. The stick doesn't move, but the signal changes based on how hard you push on the stick. It is amazing how much more control you have compared to traditional joysticks with displacement feedback.

[B Breon]

I have the full system, all 90 braking parts on an 88 car and I think it brakes better than it did with the 88 parts. I like to think that Honda changed the parts for a performance reason.

------------------
Brent Breon
Cendiv ITA #26
www.360racing.com

[ITR#231]

Greg,

Good info! What you're saying makes good sense. I guess I'll have to feel it to decide.

B Breon,
One question. When you switched to the 90 parts from the 88, did you do the rear discs too? Would it be legal to swap the 88 MC, prop valve, and front calipers for the 90 MC, prop valve, and front calipers without doing the rear disc conversion? I don't fully understand where the GCR draws the line for "complete."

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'88 CRX Si - ITA/PS2 road racer: Handles like it's on jack stands
'98 ITR #0231 - DS autocrosser: Handles like I sold it
'02 Jeep Grand Cherokee - daily driver/tow vehicle: Handles like a jumping castle