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Help w/clutch master cylinder replacement

1109 Views 8 Replies 4 Participants Last post by  Luckyman4
Is there any special trick to replacing the clutch master cylinder in a 1991 Corolla SR5? I've gotten the old one out (by unorthodox means a.k.a. brute force) and im unable to get the new one in! From where I'm at now it seems physically impossible. As im trying to put it in i either run into the wall around the strut or the black round thing right behind the master cyinder for the brakes. Help! It there some trick i havent tried? i spent about an hour and a half trying every single angle. If it's impossible, how much would it cost to get a mechanic to put it in? Thanks for any help anyone can offer.
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Not sure about this, it might help you to pick up a manual.

Moved to tech section....

I share your pain! I tried last weekend to change out the clutch MC on my 91 Corolla wagon and gave up just before I got out the crow bars and 10 lb hammers.

Problem #1: can't get a wrench on the fluid line flange nut ... well, actually I can get a stubby 10mm on it, I just can't get it to turn and the corners were starting to round off

Problem #2: The power brake booster reservoir covers the lower flange so that you can't simply remove the master cylinder. Looks like "brute force" or loosening the brake master cylinder/booster assembly enough to get sufficient wiggle room to remove the clutch MC is required.

Problem #3: All the OEM replacement cylinders I've seen have the fluid line on the side, instead of the top, of the MC; thus requiring a new line to be installed.

My latest hare-brained plan is to take my Dremel and use a cut-off wheel to slice off the original mounting bolts at the inside of the firewall so I can get the old one out without dropping out the brake MC; then cut off the old pressure line just above the flange nut - then splice in a new flange end so it can mount at the "new" off-by-90-degrees OEM cylinder; then to mount the new OEM cylinder I'll position it first and then screw in the mounting bolts from the inside of the firewall ... IF I can get in place - looks like the clutch push rod/clevis assembly are "kept" in the MC and non-removable.

All in all, this is one really poor design for R&R of a simple clutch MC.

I registered on this forum just to post my frustration and to hope that some Toyota techie can help us both out.

Tell me about your "brute force" method for removing the old one. Was it fun? Did you get to swear a lot? :eek:

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remove the brake master cylinder if you need to... also, you should be able to get to the clutch line with a regular open ended wrench...

you should take off the brake master cyl and the brake pedal too if you think it will be getting in the way. it might seem like a lot of extra work, but if it makes it more convienient, then its worth it. when you can drive around a mountain or hike over it, which would you pick? sometimes its a good thing to take the long way around...

Thanks for the reply/help. Yeah, I hear ya' on the "long way" sometimes being the better way around a problem ... [deep sigh]; I'm just ticked to have to go that route to change out a simple clutch master cylinder! It's been about 25 years since I last turned a wrench as a professional mechanic - I clearly recall cursing automotive design engineers then and the same sensation of steam pouring out of my ears occured again with this little "gotch ya!"

I can get a simple 10mm open end wrench on the fluid line, I just can't bust it loose - the corners of the nut are rounding off as I try it and there's only room to turn the wrench about 3/4" max. So I have to buy myself a 10mm flare nut wrench to get it loose (I think a 10mm crowfoot would just round off the nut also] . Meanwhile I found an online site for original toyota parts that is WAY more reasonable than my local dealership on the master cylinder (OEM "Sorta fits" $40; Dealership $99; Online original design match $55). So, I'm going to find a 10mm flare nut wrench and order an original replacement MC online ... and resign myself to having to pull the Brake MC/booster assembly to do it.

Speaking of Constitutional amendments ... I firmly believe that all automotive engineers should be required to do a "field practicum" of one year in the auto repair business before they are granted a degree ... they always seem clueless to the fact that "somebody" will have to eventually become half contortionist/half magician to actually work on their designs. I think I can get this motion seconded by anyone who's ever tried to track an intermittant dashboard electrical problem, :lol:
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yeah the electrical issues suck... ive been there tons of times. i usually go about solving those problems by running my own wires to fix the issues. (fused of course, when needed). the factory electrical manuals are key when solving electrical problems...

just use a small vise grip pliars on there, it should come right off with those bad boys. on the few engines ive taken out/put in, the vise grips are always key to get solid bolts/nuts freed. once you break it lose, then use the wrench. my brake line fittings on my car are all chewed up, but the vise grips never fail.
Yup, vice-grips would normally be the thing to try next but there isn't enough room to get even a small 6" pair on the flare nut - remember with a short open end wrench I only had about 3/4" of room for leverage ... it's super tight in that area between the brake booster reservoir and the LF strut chassis panel/wheelwell location. If a 10mm flare nut wrench won't break it loose, I'll try dropping the brake MC out and then I can "maybe" have enough room to get some vice grips on it. Thanks again! -John

OR, you can try disconnecting the rest of the clutch master cylinder and get it lose enough to move so you can fit them in :)
Heh heh ... tried that first, that's when I found out the right clutch MC mounting flange was behind the brake booster air reservoir - which blocked the clutch MC from coming forward off the firewall, hence the need for either the "brute force" method or pulling the brake MC assembly off. :disappoin
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