Hey guys,
I need to replace my master cylinder on my 74 1.8L and was wondering if there are any options out there other than droping the 2-300 bucks on the oe one or going to the 23mm one and loosing all my pressure.

I'm in brakes class at universal technical institute (rancho cucamonga, CA) right now and plan on replacing the master and brake hoses, and rebuilding the calipers but I gotta do it without breaking the bank haha.

I would be interested in going with the 23mm master if anyone knows of a good cheap replacement caliper with a bigger bore. Or even a refurbished/used master. Anything is better than what its got right now and I'll just be driving surface streets a mile to and from school till I can finish restoring her.

Any advice would be much appreciated

Thanks,
Jarin

The 19mm MC is a better match for a 914/4 unless originality is important to you. Not expensive.

BMW 3 series front calipers have also been used. I think the 23 mm master cylinder would be overkill unless you really have some large calipers that require a large amount of fluid transfer.

I would agree that the 19mm is a good idea.

914s originally had a 17mm, but they're getting a little harder to find these days.

The 19mm ATE seems to be the normal replacement and is available through many vendors, although they can typically run from the low to mid $200. range (or more).

Not sure why, but I haven't seen rebuild kits for ATE master cylinders for several years

The 914 brakes are unassisted so the bigger you go the harder it will be to press the pedal.
I bought the ATE 17mm a year ago and am very happy with it. I think that if the pedal will be harder my leg will start bothering me.

here is a link:
http://www.thepartsbin.com/catalog/?N=1698...amp;x=9&y=8

$235

I always recommend 19mm's and I never recommend the "cheapest" when it comes to brakes. ATE 19mm will give you a "slightly" firmer pedal which most people like.

Why? The answer is two simple words: "Product Liability". Or maybe one word: "Lawyers".

The Cap'n

When my MC blew out I replaced it with the "cheapest" 19mm I could find because I didn't have $200 at the time but I did have $75. There are lots of good reasons not to skimp on this part and these can be found in the numerous threads on the topic within this forum; however, when the alternative costs 125% more.... I didn't bench bleed is and t was a pain to prime and bleed.

I'm used to VW aftermarket or "OEM replacement" parts which are often the lowest quality POC's imaginable. Even so, 85% of the time they do what they are supposed to. The cheapo MC falls within that category.

I have found some excellent deals at partsgeek.com. Bought 911 power window motors, 914 master cylinder, and a host of other p car parts at great prices, with fast shipping. Try it, you'll like it.

I think you're right, but we can still buy caliper rebuild kits and brake pads.

Also, I've noticed that we can't purchase windshield wiper refills without paying for the entire blade and frame assembly anymore either. Some stupid schmuck probably installed his/her refills improperly, was involved in an accident and killed someone on a rainy day, and the lawyers pushed the blame onto the manufacturer

What a system ...

Ya I was hoping for a used/ rebuilt option to pop up or a caliper set to use with the larger cheaper cylinder that wouldnt be too much. I want to keep the project under $400

Gratuitous bashing is dumb, and blaming "the lawyers" because master cylinder rebuild kits are NLA is especially so.

P-914 only has one master cylinder...no redundant brake circuit. Failure of the component is likely to cause a lot of injury or death.

A master cylinder is a hydraulic ram, its insides need to be round and smooth. Without an accurate means to check and ream the bore, they ought not be "rebuilt." 40 year-old MC's can be pitted, oval or both. New o-rings will not fix them. A drill bit and sandpaper cannot make them round and smooth enough.

When some poor soul with a wife and three kids racks-up $500,000 in med bills and can't work after sustaining an auto accident that happened because he or someone else didn't follow the directions on a MC rebuild kit, it will not be "the lawyers" who inspire him to look around for someone to sue.

All that being said, the Cap'n is a pro who can be relied upon to properly use a rebuild kit and it's too bad he can't get one.

Check RockAuto.com. They show a range of MCs from $72 - $240. Have bought a fair amount of stuff from them. Has always been a good experience.

Did someone strike a nerve with the lawyer thing?


I've rebuilt BMW, GM, Porsche and VW M/Cs, as well as wheel cylinders and calipers, with no failures. All bores were fine, just performed a good inspection and honing ... and some of these were single circuit units. Never found an out-of-round bore.

As for the statement regarding hydraulic pressures, I don't see the difference between rebuilding M/Cs and calipers. One is a 'master' (sending unit) and the others are 'slave' (receiving units) ... both operate at the same pressure and either one could fail if rebuilt incorrectly.

As for redundancy, at least 914 M/Cs are dual circuit.

I've rebuilt a few mc's with good results and like you, never found an out of round one. How the hell does that happen? Metal cup washers??

I was refering to replacing the mc with one of a larger diameter which would reduce system pressure, requiring a larger output piston to compensate . Force = prsssure x area. So if I can get the larger mc for 80 and a set of larger calipers for around 200 it would be cheaper than the 200 to $300 mc with $100 in caliper rebuilds... Just trying to check all my options. If nothing pops up by next week I'll just go ahead with the 19mm

A while back someone gave me a "rebuilt master cylinder' similar in design to the one's we're discussing. I bench bled and installed it. It blew up while I was pumping up the lines.

You may have never seen an "out of round" bore but they also pit and groove, and if someone who doesn't know any better starts fooling around with sandpaper and a drill press, they can quickly make the bore so irregular the seal will blow at a time when it's most inconvenient.

Calipers can be fudged up just as easily as MC's but a clumsy caliper rebuild is less dangerous because there are after all four of them. When the master stops working all four calipers, no matter how many circuits the system uses, suddenly become useless hunks of metal.

That's why many folks don't like the cheap new MC's. I don't really disagree, but my experience with cheap MC's is that they have worked better than the only rebuilt MC I've used.

If a caliper fails you lose all pressure in that circuit. The 914 seems to lose both circuits when one or the other fails. The end result is a loss of all braking ability.

That should only happen if both cups in a dual circuit M/C fail. Failure is typically caused by contamination to the rubber cups. If the bore is not honed correctly and completely clean, the cups can deteriorate or tear.

A honed bore needs to be completely purged of any residue with alcohol before reassembly.

I would never recommend rebuilding an unsuitable M/C (or calipers), a good inspection is paramount for a successful rebuild.


This takes me back to the windshield wiper replacement issue. If someone doesn't know how to do something correctly, they shouldn't even attempt to do it.

Its my opinion, that there are some folks, that should only work on their cars with their checkbooks