I was just dinking around on the Napa website and stumbled across the fact that they have master cylinder rebuild kits. Anyone try one of these? I was surprised to find that they actually had a decent number of parts available for not too bad of prices.

There are not many parts on your car that are likely to kill you if they fail. Your brakes are one of them.
How much do you trust you rebuilding skills on a MC? Especially since thre are new master cylinders for not very much money.

Zach

$100 for a POS Chinese copy, or $300 for a decent one......... or $40 to use a good mc body, new seals and a new piston. I just finished up rebuilding my calipers, is this any different?

That is for you to decide. My brakes and transmission were the only parts of my car I did not rebuild. Brakes because the cost of failure was too high, and transmission because it was above my skill set at the time.

Now, I'd have a go at my transmission, but I'd still farm out my brakes for rebuild to someone I trusted.

Zach

MC's are easy to rebuild. Just a messy pain in the ass. If you open it up and it's not pitted or broken, go for it. Just clean it well and put it together just as you found it. A couple of hours and your done.

...It's not the kit...it's the person does it!

Pits and such are the key. If you don't have the proper hone and procedure, you will not get them to function properly.

Pitting is the main reason cast irom master cylinders fail, and you can't hone 'em out. You may THINK you can, but there's a real good chance you're wrong. If you brought your car into my shop and told me you'd rebuilt your master cylinder, I wouldn't test drive it, nor would I ride with you.

Real rebuilders sleeve the bore.

The Cap'n

I found that part number on-line as well, but when i tried to order it (from the store) it came back as no longer available. I never did attempt to order it on-line though.
As for rebuilding them, I wouldn't hesitate, it is not that difficult. Just confirm that it is rebuildable. The typical failure is not pitting it is the seals. I don't understand this fear from others. Has anyone actually heard of a total failure? If you're confident enough to do the job and do it right there shouldn't be any problems. If you did it wrong you would know it prior to even driving the car. After all it would need to be bled. Failure would be evident.

I don't get why everyone's afraid either. If the body is rebuildable you're going to know that there's something wrong from a leak while bleeding..........which is not going to be complete failure, just a leak. And if is working without leaking during bleeding it's not like it's going to decide in a month to completely fall apart.

So what's the difference between pitting in a master cylinder and pitting in a brake caliper? My calipers are sure working great without leaking.

IMHO - stick with ATE - either kit or MC's, since they were OEM/OES & great quality. If in doubt, PM or email to Eric at PMB & ask the brake guru!

MC rebuilding is pretty easy and straight forward. as stated earlier make sure you dont have major pits. small ones can be honed out. i would check for pits before spending money on the kit. if the MC is to pitted just buy a new one. sleeving is really expencive. i had to get that done on my morris minor. as for inpending death from MC failure you'll know if your rebuild was a sucsess while bleeding the system afterward. and i have rebuilt several MC even had 1 failure. its not a total catostrofic nightmare the pedal just starts getting softer and softer you'll know you screwed up way before you die in a firey car crash.

Oh doom and gloom, you incapable mortals......... Ah shucks just rebuild them, it is a simple task just follow directions, do it right is not hard for most of us folks, this is a simple operation.
if there are signs of rust even pits that you can feel or see, feel free to try to hone them out, if you can, then you saved the expense of a new cylinder! of course there is a limit to how deep you can hone, so really bad ones might not be honable. I have honed rust out of many a cylinder, just besure to inspect everything and clean it up well when done. I guess I am not real???


the only thing I would be concerend about is poor quality seals, but heck even ATE brand seals can be compromised if not stored right or contaminated.


One thing I learned, for sure is brake fluid burns the eye badly, so i wear glasses when working brake fluid

I rebuilt one once. Put it back together, bled the brakes, and took it for a spin around the block. Worked great. Next day went on a ski trip up in Big Bear. After a day of skiing I get in the car and the brake pedal went right to the floor. WTF! Got the car home and took the MC apart. Nothing wrong that I could see. Put it back together and could not get it to work. Only new MC from then on.

I've never rebuilt one on a 914, but I did my front brake master cylinder on an 89 Kawasaki Ninja 750. It was pretty easy and they never leaked.

I would personally be more afraid of installing some of the after market suspension components I've seen than i would of rebuilding a master cylinder.

Back in the day, I was a Chrysler factory trained brake at front end mech at a dealership in OKC. Before the innovation of disc brakes, We regularly honed and rebuilt wheel cylinders, but never a master. We would have lost our certifications if we were caught rebuilding a master cylinder. I would never rebuild one and send one of my friends or relatives out in that car. Their lives are worth more than a few hundred bucks to me.

Did my datsun pickup when I was 17. The early ones are easy to do. I wouldn't hesitate to rebuild mine if the bores are good.

So you've saved a couple of hundred bucks!! Best take that money you saved and spend on increased liability insurance so they don't take everything you own, or will ever own .....................................

The Cap'n

Don't be sore cause i'm better at rebuilding hydraulic systems than you

I'm not. Just promise me you'll never be on any road where I, or any of my loved ones, are driving. Especially not behind me.

The Cap'n

Don't worry, the way I drive, i'll never be behind you

Bold words. Good thing it's not a challenge .........................

The Cap'n

Well while this has been fun..... only one person has hit on the point I was looking for. Napa has the kit in their system, but it's an obsolete part. I double checked today and no luck.

I was hoping for a different result. I'm starting another car and was hoping to rebuild rather than replace.

if you put new seals in one and it did fail, I doubt it would go straight to the floor with zero brake presure. if it were to fail, it would give ample warning and still stop the car. sensationalism, propagated by the media for mass consumption, has permeated the fabric of our pussified society.
I fought for your right to have a different opinion or choose what you want so here are some choices:
grow a sac, hike up your skirt or pay a pro to do it

Maybe somewhat off the topic, but I have about three hours driving time on my 320i brakes, and it stops really well. The biggest improvement was bleeding the lines at the proportioning valve. Still thinking of doing the MC bracing off the steering rack, it just makes sense on our old cars. Hell, in the driving i have done, with GOOD stopping, my rear discs are hardly getting used.

Read carefully: The one that I rblt that failed after 1 day failed completely, instantaneously, and with zero warning. There was no leakage and the reservoir remained full. It was assembled correctly. If you are a pro I am amazed that you would undertake such a penny ante job and expose yourself to such liability.

If properly inspected there is no reason why this wouldn't be fine. I don't know what everyone's problems is..... WE'RE NOT DRIVING TOYOTA'S... and I think that was more a problem of poor footwork than being a Toyota problem.

With that said I help design test and build parts all the time at work that could kill someone.... or many people. If you're careful and inspect it carefully you have nothing to be afraid of.

brp986s if your master cylinder went out like that I would think you probably pinched a feed line to the reservoir or something like that. The fluid doesn't magically disappear and the seal doesn't magically disintegrate. I probably wouldn't have bought a new master cylinder in that case just out of pure curiosity as to why it decided to quit working.

some people have skills and some dont. I know what not to rebuild.
if it was correct it would not have failed.
I commend those who know when they should not cross that line. brp, ya dun crossed that line.

When I was a kid I couldn't afford to throw bucks at a car and had no choice other than to rebuild. As mentioned earlier, the biggest PITA is the mess if a slave or master fails. You'll learn what's rebuildable and what's not. And without killing yourself or someone else (unless your some fool idjeet). I also like to polish after honing, too. In Krusty and other professional mechanics defense, I understand their position on this. I wouldn't want me working on my car if it were me.