how does a pushrod to a brake's master cylinder change position?

'92 Honda Accord LX whereby the front brakes aren't releasing properly. I've changed the MC as it was leaking onto the braker booster outer shell. The brake booster shows no
sign of fluid internally with the MC removed. I have minimal freeplay between the brake pedal & the back of the pushrod - I move the pedal ~ 3mm before contact with the pushrod. It appears from reading tegger's info I may need to adjust the pushrod - how could it suddenly change when it is locked in place and been functioning properly for years?
TIA, Ross
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Sticky calipers???
G-Man

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I agree - seems to be a reasonable possibility, although I'm surprised both sides would stick at the same time. Would like to have some best guess opinions before I start swapping out more parts. Neither is leaking and the left front is grabbing more than the right.
Thanks G-Man

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I'm going with sticky calipers - removed both - right side has rubber damage and may have leaked at one point, although there was no fresh fluid - just a dirt caked dark area. Will post the results in 2 days when I receive the calipers and can install. I'd still like to hear opinions too. Thanks in advance.

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sticky calipers it was! problem resolved.
Thanks to everyone ... appreciate the input very much
"Ross" wrote:

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All master cylinders are NOT created equal...
JT
Ross wrote:

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On Mon, 12 Jun 2006 19:15:22 GMT, Grumpy AuContraire
This fact would apply to a MC/pushrod working fine before a change and then malfunctioning after. In my case the problem started suddenly before any work was done. I then started looking carefully as to why - which is when I saw leakage from the MC and replaced it - problem still exists so now I'm trying to guess at what the next cause may be. I am about to adjust the pushrod to see if a change in functionality occurs. Any other guesses appreciated.
Thanks, Grumpy auContraire

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I move the brake pedal slightly to make contact with the pushrod and then move the pushrod ~5mm easily - with no resistance - before it contacts the MC. This I am confident of. No adjustment needed as I see it.
Haynes manual - Honda Accord 1990 thru 1993 All models indicates: Dragging brakes 1. Incorrect adjustment of brake light switch 2. Master cylinder pistons not returning correctly 3. Restricted brake lines or hoses 4. Incorrect parking brake adjustment
1. I don't believe it is this as it visually appears to function ok and has not been touched to become misadjusted. 2. Replaced MC - bench bled prior to install. 3. Bled all wheel cylinders to replace all old brake fluid in the system with no noticeable problem of fluid movement through the lines. 4. Parking brake applies to rear brakes - my problem is definitely on the front.
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Are you sure? If so, then the pushrod adjustment is fine.

Not if you actually do have freeplay.
How to check the calipers: Remove caliper from mount bracket and hang it from the upper A-arm with some wire Watch caliper piston while helper presses pedal to the floor Piston should move out immediately when pedal is pressed, but move back in slightly when the pedal is back up again.
If piston does NOT move in when pedal is released, the piston may be stuck. Eject piston about 3/4", spray brake cleaner to remove dirt from dust boot, then lift dust boot back from piston. Is the piston black and brown?
Each full pedal press moves the front piston out about 1/16". Each full pedal press moves a REAR piston out about 1/4".
--
TeGGeR

The Unofficial Honda/Acura FAQ
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My '92 doesn't have a removeable knee bolster so I removed the seat so I could get a reasonable perspective on what is going on. Having eye glasses (old age) I was finding it hard to focus and get a clear sense of the action. As I mentioned in another thread all seems good from my understanding of things. Thanks for confirming here though - sure do appreciate it.
Dam, wish I hadn't removed the calipers yet so I could test them as you describe below. NAPA had a listing for 2 types so I needed to bring one in to get a match. I removed both as I was gambling on being able to give mine to them for core value and walk out the door with rebuit ones. They had one type in stock .... turned out I need the other, so they've been ordered and will be in day after tomorrow. I will save this info for future reference as I don't want to reinstall, bleed, remove and test. The car has over 290K and I pull a small utility trailer on occasion so good brakes is imperative. Out of interest, at 284K I was at the top of Roger's Pass, BC with the following load: all weight in kg loaded empty total weight 2650 1530 rear wh & trailer 1900 790 trailer only 1000 240
trailer pulled great (std. transmission) but slowing/stopping was very poor, so I had to always anticipate, downshift as much as possible and descend the mountains like a big rig - slow from the top to the bottom. I drove from Kelowna, BC to Kenora, ON - Lake of the Woods - 200km east of Wpg. MB

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Ross wrote:

it's not the pushrod, it's the calipers. take the calipers off, pump the pistons all the way out and recondition them.
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Thanks jim. I've jumped to that conclusion now. Appreciate your opinion too. NAPA doesn't carry rebuild kits - just rebuilt units. So to save me time & effort I'm going to replace both front.
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Ross wrote:

Sounds like we are in the same boat..see my thread about 92 accord brake calipers...which version do you have, are the caliper pins bolts that thread directly into the caliper ears (US model) or are the caliper ears regualr holes and a small bolt threads into the caliper pin? (Japan version). I seem to have the Japan version on my USA built Accord???
Mark
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