Brand new brake reservoir failure

[KevAndAndi]

Beautiful Saturday. Wife and I about to go to dinner in the Spider. Doing my usual pre-drive look under the hood. Find a stain on the floor under the master cylinder. Then discover that one of the two fittings on the bottom of the brake fluid reservoir has completely broken off, draining the half of the cylinder toward the passenger side. I installed the reservoir just a couple of months ago and we have only driven the car a few miles. I had inspected the reservoir numerous times before and never saw anything amiss or any leaking fluid. The failure was 7 or 8 millimeters above the hose clamp, which I had been careful not to make too tight.

What could have caused this seemingly spontaneous failure?

[Odoyle]

Seems like an odd thing to happen, considering you just put in a new hose. Did the lower tube break off? Or did the hose simply slip off? Earlier this week I removed my brake reservoir to clean it out and replace the hoses (by the look of it I replaced mine with the exact same hoses your using) while installing a new master cylinder. I decide to use the O.E. clips I took off the old hose along with a special clamp similar to that used on the rubber boot on the rear brake compensator and it has worked great. No leaks... so far. I purchased them from my local True Value hardware store for a few cents each. Now I'm not saying these are the holy grail for this job... but it has worked for me.

[azruss]

how stiff is the new hose. may have put enough side pressure on the nipple to bust it off. How soft is the plastic on the new tank.

[KevAndAndi]

Seems like an odd thing to happen, considering you just put in a new hose. Did the lower tube break off? Or did the hose simply slip off? Earlier this week I removed my brake reservoir to clean it out and replace the hoses (by the look of it I replaced mine with the exact same hoses your using) while installing a new master cylinder. I decide to use the O.E. clips I took off the old hose along with a special clamp similar to that used on the rubber boot on the rear brake compensator and it has worked great. No leaks... so far. I purchased them from my local True Value hardware store for a few cents each. Now I'm not saying these are the holy grail for this job... but it has worked for me.

That is a really cool clamp design which basically operates in the same safe manner (designed to prevent over-tightening) as a fuel injection clamp but without a screw. I'll see if I can find some at my local store.

To answer your question about the nipple: It completely sheared off.

[KevAndAndi]

how stiff is the new hose. may have put enough side pressure on the nipple to bust it off. How soft is the plastic on the new tank.

You are actually the second person to suggest that, which is a reasonable theory, but I really don't think that was the proximate cause. The hose is not stiff, and I provided so much slack, I don't see how the stress could have, or should have, made the nipple fail.

My best guess is that there was an imperceptible defect that heat and the gentle strain of the hose exacerbated.

[KevAndAndi]

By the way, if the car was driven with this condition, does it mean that air has gotten into the master cylinder?

[azruss]

if the hose stayed elevated above the mc you are probably ok. If you got air in the mc, you would feel it.

[SpiGirl75]

Ours broke in exactly the same spot using the same blue hose. We installed it in our 75 that we are restoring and hadn't even driven it.
We bought a new reservoir and the plastic clips that hold it in the bracket from Spiderroadster and it looks to be a different brand than the one that broke. We'll see how it goes.

[KevAndAndi]

Ours broke in exactly the same spot using the same blue hose. We installed it in our 75 that we are restoring and hadn't even driven it.
We bought a new reservoir and the plastic clips that hold it in the bracket from Spiderroadster and it looks to be a different brand than the one that broke. We'll see how it goes.

For what it's worth, the reservoir that broke was "Made in Yugoslavia". So, while it may not have been New Old Stock, it was certainly New Not-Young Stock, seeing as how it came from a country that no longer exists.

I just received a new reservoir from the same vendor, and this one was made in Red China. So, I'm hoping that the completely different factory will mean that the product will not suffer from the same (presumed) defect. The molding of the Chinese reservoir looks a little neater than the Yugoslav one's, but there are some spots where the plastic is white and opaque rather than translucent. Not sure if this indicates a plastic defect or merely an aesthetic flaw of no consequence. We shall see.

The original reservoir was crumbling when we bought the car in Oct. 2014, so I have been trying since then to (among many other things) get this sorted - a part that is quite simple and should be fairly robust! I hope the third reservoir is the charm.

[SpiGirl75]

Our reservoir that broke was also made in Yugoslavia. We hope you were able to get an exchange. We were told our installation was less than stellar and offered free shipping on another one.
Not sure of the manufacturer of the one we bought from SpiderRoadster.

[KevAndAndi]

Our reservoir that broke was also made in Yugoslavia. We hope you were able to get an exchange. We were told our installation was less than stellar and offered free shipping on another one.
Not sure of the manufacturer of the one we bought from SpiderRoadster.

Very interesting. Was it the nipple closer to the engine that broke, as mine was?

Because this vendor has offered great service, I was actually the one who offered that same deal: I'll pay for a new reservoir and you, the vendor, pay for overnight shipping. To be fair, I couldn't be certain the break was due to a defect, so "splitting the difference" seemed a good compromise.

Now, though, we have anecdotal evidence of a systematic manufacturing defect. Therefore, I would advise folks to request a reservoir with something other than Yugoslavia stamped on it.

To be clear, I will continue to do business with the vendor because I don't think they were knowingly selling a defective product.

[SpiGirl75]

Yes, it was the nipple closest to the engine that broke after the car had been sitting in the garage with brake fluid in the reservoir for two months.
We will also continue to buy parts from that vendor as well as others who have the items we need in stock. In this case we didn't want to install the same brand reservoir as we felt the first one was probably defective.