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Discussion Starter · #1 ·
Many of us, myself included, know that the rubber flex hoses can fail internally and cause problems with brake calipers failing to fully retract, and clutch engagement becoming wonky. This month the feel of the clutch pedal on our 86 Spider began to feel weird. The pedal was not returning as quickly as I was raising my foot. The problem was the hose; no surprise. What was surprising, was that the hose was just 25 months old (purchased and installed 25 months ago). It was replaced with a new master and slave cylinder at the same time. About 1500 miles driven in those 25 months. The fluid was clear, and other than the slow retracting pedal, everything was in order. FYI, I have been using Valvoline DOT4 "Synthetic" brake fluid for decades in this and dozens of other cars with no similar problems. The new parts were purchased (25 months ago) at either Difatta, or Centerline. The hose is Pirelli stamped with other numbers, etc. In the image below, you see how I cut open the hose to reveal the inner hose that carries the fluid. The rubber on the inner hose had become VERY gummy; I could easily scrape the gummy rubber away from the ID with my finger nail. Very disappointing. I replaced the defective hose with the stainless steel braided "upgraded" (I hope!) hose that Centerline offers. Now, the clutch pedal feels great again.
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At the risk of igniting a lively discussion on brake fluid, I have never used anything but Castrol DOT 4 in our older Alfas. I tried out a Valvoline synthetic fluid years ago on a Suzuki bike I had with double discs at the front, and I had brake hose problems within months. I assumed then, and I still think today it was the fluid was not compatible with the OEM brake hose material. After all, it was an old 1974 vintage motorcycle.
Rubber compatibility with the media is a very important issue.
 

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Discussion Starter · #3 ·
Well, of course I have considered this. I am a firm believer in routine brake fluid maintenance and have used this fluid in countless vehicles over the decades without issue, as far as I know. But, of course this is a possibility.
 
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Dom, perhaps… As I said, it was recently purchased. If in fact they “go bad” in the package, maybe they should include an expiration date.
 

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Well, andylarry I must admit sounds like you're more exacting than I am about brake fluid changes! All rubber products have a useful shelf life but it's a heck of a lot longer than 2 years, or even 5 years in most cases.
What is puzzling in this case is that it's a Pirelli manufactured part, one of the world's leading rubber products manufacturers. But based on what you revealed here, that rubber compound did not like the brake fluid. EPDM rubber is still the most commonly used compound for brake fluid applications like ours, but many rubber compounds are proprietary and one manufacturers EPDM will not be formulated exactly identical to another's.
Regardless, this is indeed surprising and disappointing for a brand name part, unless it was literally decades old.
 
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I haven’t seen a new Pirelli brake/clutch hose at least ten or more years.
 

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I can't imagine this to be a fluid compatibility issue. All DOT3/4 brake fluids are glycol based and are tested for compatibility. "Synthetic" in the context of brake fluid is just a marketing term.

I'm thinking you just got a bad hose.
 
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I haven’t seen a new Pirelli brake/clutch hose at least ten or more years.
Well... now that's something to think about! It leads me to think about the comment about a possible counterfeit part.
 
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At the risk of igniting a lively discussion on brake fluid, I have never used anything but Castrol DOT 4 in our older Alfas. I tried out a Valvoline synthetic fluid years ago on a Suzuki bike I had with double discs at the front, and I had brake hose problems within months. I assumed then, and I still think today it was the fluid was not compatible with the OEM brake hose material. After all, it was an old 1974 vintage motorcycle.
Rubber compatibility with the media is a very important issue.

ATE brake fluid works well too!
 
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Braided stainless? Problem solved?
please be aware that there are many kinds of “ braided stainless” hose available.
In all my years of hot-rodding I would ONLY go to aircraft specialty licensed/ certified shops that use first line mil-spec high pressure braided hoses.
I would bring my Euro fittings and they would cut and braze the fittings to US mil spec fitting and measure the calculated movements of the lines and build a line in the appropriate length and angle fittings. Nothing beats certified mil spec aircraft stainless braided lines of inert material ( “Teflon” like). Do not cut corners in brake and fuel lines!
 

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But Mad North-Northwest
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All the braided stainless hoses I've seen from the Alfa suppliers are at minimum DOT compliant. The Goodridge ones that Centerline and Classic Alfa sell are DOT/TUV and are individually pressure tested. I don't know anyone who's selling janky stainless hoses for Alfas.
 
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please be aware that there are many kinds of “ braided stainless” hose available.
In all my years of hot-rodding I would ONLY go to aircraft specialty licensed/ certified shops that use first line mil-spec high pressure braided hoses.
I would bring my Euro fittings and they would cut and braze the fittings to US mil spec fitting and measure the calculated movements of the lines and build a line in the appropriate length and angle fittings. Nothing beats certified mil spec aircraft stainless braided lines of inert material ( “Teflon” like). Do not cut corners in brake and fuel lines!
I’m not suggesting any source is “wanky”.
I am commenting that “stainless braided” is not the sole description to determine quality.
Certainly DOT/TUV are valid qualifiers. However my personal experience is nothing tops AN mil spec certified high pressure fuel and hydraulic flexible hose lines.
 
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