Prelude Master Cylinder Upgrade

Ah, my woes with brakes. It's endless. I either have a leaky brake caliper or a low/soft pedal. Understandable, since I have Wilwood 4 piston calipers matched with a CRX Si Master Cylinder and a CRX HF Brake booster. However, I have never had brake fade! I just don't have the confidence in my brakes that I should, after all, it's a 2051lb car with 11" rotors and 4 piston calipers... it should stop on a dime.
After hearing/reading plenty of people speak to the Prelude/4dr Civic Ex Master Cylinder, I'd figure I'd give it a try. After the March 23rd event at NASA, it was time.

The install is pretty straight forward, so I'll give a quick install guide and tools needed:
'89 Prelude 2.0Si Master Cylinder
12mm socket/wrench
10mm open ended wrench
Brake fluid
Brake cleaner
An assistant to fetch you something to drink
Jack stands
Jack (to raise the car, not one of your idiot friend's named Jack…however, he could fetch the drink?)
something to open the brake bleeder valves (mine are 10mm for the rear drums and like 1/8 for the fronts)

1. Begin by loosening the brake lines to the master cylinder in the car, but don't disconnect.
2. Remove the 2 12mm bolts holding the MC to the brake booster.
3. Place a rag under the MC and remove the brake lines.
4. Remove MC from car and empty the old brake fluid from the reservoir.
5. Remove the reservoir from the MC (10mm bolt).
6. Inspect the reservoir and filter, making sure both are in good shape.
7. Clean the reservoir and filter with the brake cleaner.
8. Bring the NEW MC to the car and test fit it. You'll notice that one of the lines doesn't fit properly (look below for pictures). The Prelude MC has the brake inlet lines at a different angle, which require some bending.
9. Bend the lines so that they fit properly in the new MC. Don't be worried about snapping them...just avoid creasing them.
10. Clean the new MC with brake cleaner.
11. Install the reservoir/filter onto the new MC.
12. Bench bleed the new MC (most remanufactured MC's come with instructions, follow them).
13. Get assistant to get you a drink.
14. Install the MC in the car. Bleed the brakes (Left Front, RR, RF, LR)
15. Drive the car and test it. You'll notice that the brake pedal is much firmer.


PICTURE TIME!!! weeee...


Shiny and new...


Here's the real difference in braking power. The Prelude is 15/16".


Here's the other real difference. As you can tell, the brake line inlets are different.


And the final difference. The "tanks" are different sizes for the CRX.



a better look at the differences in the angles of the brake line inlets.

Impressions:
Well, it works. With the CRX MC, the brakes would work with the pedal halfway down. Now they work near the top of the pedal's travel. I had a helluva time trying to get the brakes to lock up, but it's because of the HF brake booster (next upgrade). I somehow got rid of my mysterious brake squeal! I'll have to find out how well they work in May when NASA runs the West Coast Honda Challenge here in Vegas.


I'm making another for the fricking sway bar endlinks that troubles sooo many

http://kazs.info/kam/index.html
http://kazs.info/kam/preludemc.html


[Modified by Driven, 8:52 AM 3/27/2003]

 

thank you for the informative post... I am trying to figure out what master cylinder fits on my 90 si hatch with a stock brake system...

what pads/fluid do you run?

 

Is the Preludes M/C the same size as the EX's?? Cause I thought that they were and I thought that the EX's bolts right on no need to bend any of the lines? I could be wrong I have yet to do it but hey if the Preludes M/C is cheaper that would be the way I would want to go!! Cause I heard that the EX's M/C was pretty expensive?
*EDIT* Oh and by the way thanks for the write up!!


[Modified by Vinceg99, 2:32 PM 3/27/2003]

 

great info
driven, what are you using for rear brakes?


[Modified by limoZeen, 2:43 PM 3/27/2003]

 

You can use the Prelude MC or a 4dr civic EX. They both will provide a better pedal feel.

I'm using some off name brake pads ( i want to say they are Polymatrix pads) and motul 600 brake fluid.


I believe both are 15/16ths... I can't confirm or deny the civic's MC fit. I would suspect they (prelude and civic) is identical.

The Prelude MC from autozone was $39.99 with $20 core. The Civic was $59.99 with $20 core.

I opted for the Prelude due to expense... they are the same size, so will provide the same "performance".

I'm using factory issued '89 CRX si rear drums. I have not found a reason to run rear discs. I can't get fade with the current setup nor do I want to add more weight to the car (which the rear discs will do).

 

I just installed a 4door Civic EX Master cylinder, it is a 15/16ths and the brake lines fittings were in the exact same location as my stock MC.

No need to bend any lines. I paid $45 at my local Van's Auto Parts.

 

If you have the money and want to upgrade the brake booster I would use an Integra M/C and brake booster. The 90 Integra 4door w/o ABS has a 1 inch master cylinder which will bolt to the brake lines in their stock location, only thing is you have to use the Integra booster which isn't cheap and is not easy to install.

 

Thanks for the informative post. I'll try this sometime in the future
to you.

 

What makes the integra booster NOT easy to install?

 

great post, thanks!

 

So If I tommorrow were to go get a 91 EX MC and slap it on my 91 SI Booster, I would undoubtedly have a firmer pedal? What else would I gain? Reason asking is my cylinder is acting up.

 

yep. MC and the booster just allow you to modulate the brake pedal better (or worse).

Bigger MC allows you to push more fluid to the calipers.
Bigger boost requires less effort to push the same amount of fluid.

 

You have to crawl up under the dash to disconnect it.

 

I would only upgrade the master cylinder if you plan on upgrading your brakes. If you put bigger calipers on, they'll require more fluid. I upgraded mine cuz it was blown and I plan on upgrading the front brakes someday. Like driven said it's all about pedal feel.

 

this is one of 3 threads i actually have bookmarked =P

 

I nominate DRIVEN for president heheh

damn i love the way you always do these informative post. Gotta love the detail and dummy proof step by step instructions. As for your two link(click-SAVE as favorite)

Good job this is why i love honda-tech and it's memebers!

 

Oh you pansy! suck in that gut and grab a socket and an elbow!



Of course, mine's a bit easier to get to since i'm lacking underdash clutter.


And thanks for the compliments. I do this for those who have no clue what to do or what to look for. When I started doing a lot of my mods, I had no resource to look at and research on what to do. So, i figure I'd start cataloguing these "mods" i do.

 

Yes I am definitely a pansy, I even had the 1 inch M/C and returned it to get the 15/16ths one. I had busted my ribs snowboarding and decided to take the easy pain free route of not crawling up under the dash.

BTW, note for those getting the booster, go to the junkyard to get the booster, parts store quotes were $130 to $200.

 

how much more weight would the rear disk add? i think about 5lbs each side which is not bad. personally i like rear disk i just did the swap a couple days ago, it was easy i followed fourthgenhatch how to guide and it was easy.no more messing with rear drums, it was hard for me to change the pads of the drums. im going to change the proportioning valve 2morrow, im also going to do the 90 prelude si m/c since u guys talked about it and how good the pedal feels. thanx for the info guys im going to bookmark this thread.

 

Can anybody here confirm the 90 teg 4 door has a 1" MC? I cant seem to find any dealer/junkyard with a 1" MC for those, only 15/16". If its true, Id love to get a part # or something.

Thanks.

 

will the 93 integra booster mount to the civic? i have the 93 teg and the brakes from it can i unhook it and mount it to the civic?