HF HNBR O-Rings: Safe for long-term fuel exposure?

[The Critic]

Had to remove the fuel dampener (part of the fuel rail) in order to perform some repairs on an engine. The o-ring on the fuel dampener was damaged during the removal process. My pack of HF HNBR o-rings has the correct size. However, is this material suitable for long-term exposure to gasoline?

 

[spackard]

I'd say no. Seems I remember wanting to one day and rubbing an HNBR O-ring with my fingers and some carb cleaner and it disintegrated. Go with nitrile rubber.

 

[andyd]

Early E-28s had fuel line dampeners. Later yrs didn't. They tended to leak. and were unnecessary

 

[tom slick]

HNBR is an enhanced nitrile rubber and listed as excellent for exposure to fuel and oil and high temperature.

 

[wings&wheels]

I am an HF fan generally, but am wary about using their stuff in critical applications like fuel. You are probably safe, but I'd be temped to let one soak in fuel for a bit before I commit, if you have the time.

 

[ron350]

Critic if you like fire use HNBR o-rings to seal gasoline lines.
HNBR should not for use with gasoline
HNBR is just Nitrile (Bina-N) souped-up so that it can have a higher temp rating.

Viton (Flurocarbon) or souped-up Viton are the only o-rings designed for today's gasoline.

PS: The quality of HF Viton o-rings are so poor I would not use then on a lawn mower.

 

[Trav]

HNBR is good for gasoline, I don't think I would trust HF though.

https://www.marcorubber.com/o-ring-chemical-compatibility-chart.htm

 

[edhackett]

Originally Posted by Trav
HNBR is good for gasoline, I don't think I would trust HF though.

https://www.marcorubber.com/o-ring-chemical-compatibility-chart.htm


HNBR is not recommended for gasohol, as it has poor compatibility with ethanol according to that chart.

Use quality viton (ETP) for all fuel applications.

Ed

 

[bmwpowere36m3]

I wouldn't trust HF o-rings based on what I've seen. Poor molding, flash and QA. Can't you get this o-ring from the dealer?

 

[ron350]

Trav I have to disagree with you on this.

Unless they have changed something in the last few years Nitrile and HNBR will degrade when exposed to gasoline. I don't think you are going to find any Parker o-ring catalog that recommends HNBR to be used with gasoline.

http://www.parker.com/literature/O-Ring Division Literature/ORD 5700.pdf

https://www.oringsusa.com/

http://www.theoringstore.com/

 

[Trav]

Originally Posted by bmwpowere36m3
I wouldn't trust HF o-rings based on what I've seen. Poor molding, flash and QA. Can't you get this o-ring from the dealer?


True, I forgot gasoline is not gasoline anymore. My bad.

 

[ccs368]

I believe gasoline applications typically uses Viton rubber. Buna-N or HNBR has stronger strength and good for gas but Viton is excellent for gas. IMHO, I think I would go OEM in this situation just because of my fear for a highly critical sealing and don't want leaks.

 

[daves66nova]

Go to www.theoringstore.com they have a great selection of o-rings very inexpensive.

 

[ron350]

You don't have to take my word about HNBR conduct a simple test yourself.

Take two new HNBR o-rings that are the same size.
Find a clean glass container like a baby food jar and put enough gasoline in to cover the o-ring.
Put one o-ring in the jar of gasoline and put the other same size o-ring in a plastic bag and label it.
One week later take the HNBR o-ring out of the gasoline and compare it with the one in the plastic bag.
The untouched HNBR o-ring in the plastic bag will have magically shrunk.

 

[ccs368]

Oh, and the last thing is I don't think any vehicles especially Japanese follow the SAE AS568 standard for fractional sizes with fuel rails which your o-ring container uses. It's probably metric sizing so even though it may appear to fit, the gland, major OD, and well dimensions won't allow a proper squish on the o-ring profile so again, my recommendations is not so much material compatibility but more of dimensional fit up concern.

 

[Kruse]

I've been into HF stores and I HAVE purchased a few items from HF. However, I wouldn't trust the o-rings just because of their previous track record with other replacement parts.

https://images.harborfreight.com/cpi/recalls/fuse_sets.html

If you do a Google search for other HF recalls, other things show up also. No reason to risk it.

 

[JHZR2]

Originally Posted by ron350
You don't have to take my word about HNBR conduct a simple test yourself.

Take two new HNBR o-rings that are the same size.
Find a clean glass container like a baby food jar and put enough gasoline in to cover the o-ring.
Put one o-ring in the jar of gasoline and put the other same size o-ring in a plastic bag and label it.
One week later take the HNBR o-ring out of the gasoline and compare it with the one in the plastic bag.
The untouched HNBR o-ring in the plastic bag will have magically shrunk.



As I understand it, older rubber fuel hose is nitrile/NBR. Newer ones have a fluoroelastomer liner to deal with alcohol and diesel additives.

 

[spasm3]

Hf does have nitrile o-ring sets.

 

[The Critic]

Thank you for the information. Since this is a critical application (fuel pipe which connects the damper to the fuel rail), I decided to buy the o-rings from the dealer.

I did have one of the green HNBR O-rings in service for one day without issues, but it did get a bit softer.

 

[WyrTwister]

I have the HF green o-ring kit . I bought it for A/C work . Is that OK ?