Visit our Popular Forums

flynmike · 06-17-2013, 12:01 AM

I had hydraulic/disc brakes installed on my trailer around 5 years ago (Inland RV did an awesome job) and I have never had any problems...until today.

I picked the trailer up from storage to bring it home to prep for a trip this week. As part of my procedure when I pick it up the first thing I do as I start to roll I check the brakes. Today was no different and they worked fine. As I drove home I noticed the rig felt funny and I realized I wasn't getting any braking from the trailer.

When I got home I checked the brake reservoir and it was empty. I looked under the Airstream and found the left rear tire wet with brake fluid. I crawled under and looked a the caliper and brake line and just by chance felt the line where it connects to the caliper and found it loose! I was finger turning loose. I screwed it in finger tight and I'm going to investigate further tomorrow.

Anybody EVER see or hear anything like that? I mean it's been great for years and now finger tight! I took a 1500 mile trip a few weeks ago and no problems. What could cause the line to unscrew short of someone messing with my trailer?

Any thoughts are appreciated.

Mike

ROBERTSUNRUS · 06-17-2013, 12:39 AM

Hi, I could be completely wrong, but I would suspect tampering especially since you mentioned "storage."

cwf · 06-17-2013, 05:03 AM

I would "report to storage"!

Lines don't loosen in storage.

Skater · 06-17-2013, 05:24 AM

Yikes. I would argue it could have loosened over time, and there's no way to tell. Would threadlock be appropriate for that usage? I'd check into that. If it was sabotage, it would make it that much harder for someone to do it.

**GCinSC2** · 06-17-2013, 05:57 AM

Sounds very uncommon but a pic of the configuration might be helpful. FWIW I'ver never heards of applying any threadlocking to blake line fittings. If someone put a wrench on it, I'd expect that it would show fresh wrench marks compared to the other fittings.

Glad no damage to rig to report.

dznf0g · 06-17-2013, 06:20 AM

Applying thread lock introduces the possibility of contaminating the fluid.....be careful. I have seen a factory applied locking, or gripping, material applied to the threads. it is dried and "rubbery" when purchased. I don't know what the sealer is.

**Action** · 06-17-2013, 09:07 AM

Possible causes would be tampering or an installation/servicing issue.

Doubtful you will find the cause. And checking the other lines with a line wrench would be prudent. The lines and fittings should be double flared at the end as a safety measure. Do not use any chemicals in or around the brake hydrallic system. Contimation of the brake fluid may cause issues with performance later.

>>>>>>>>>Action

Skater · 06-17-2013, 09:22 AM

Yeah, the contamination was what I was afraid of with the threadlocker. And on one car I worked on, the fittings were so soft that I had trouble getting them undone without rounding them; any additional resistance, including threadlocker, would've meant just destroying them. I'd worry about that issue, too.

**Action** · 06-17-2013, 09:46 AM

Using a line wrench will grip the fitting on 5 points versus 2 points. Giving better torque for tightening and loosening steel fittings. Highly recommended to reduce damage on fittings.

>>>>>>>>Action

ROBERTSUNRUS · 06-17-2013, 10:01 AM

Quote:

Originally Posted by Action

Using a line wrench will grip the fitting on 5 points versus 2 points. Giving better torque for tightening and loosening steel fittings. Highly recommended to reduce damage on fittings.

>>>>>>>>Action

Hi, always use a line wrench on these type fittings. [brake, fuel etc.]

Aerowood · 06-17-2013, 10:10 AM

You could also have a broken flare, this would cause the line nut to feel loose, it would work with one application and fail and then not work again.. I would remove the fitting and check the flare.

flynmike · 06-17-2013, 10:45 AM

It was dark last night when I found the source of the failure so I took a good look at it this morning in the daylight. Impossible to tell if someone put a wrench on it and I can't tell if something might have been kicked up from the road and knocked it loose.

I haven't bled brakes in too many years to count. I've got the line wrenches and I found the procedure doing it on the Carlisle website but I think I'll find a local brake shop and have them check the flare and the rest of the system. I've lost my edge for that sort of stuff.

Jammer · 06-17-2013, 04:34 PM

I doubt anyone did it on purpose.

The obvious explanation is that it wasn't torqued properly at the time of installation.

The less obvious explanation is that it might have vibrated loose if it was installed in such a way that there was mild counterclockwise torque on it. There is more than meets the eye to the design of brake lines. Many if not most automotive disc brake installations use banjo bolts at the caliper because they aren't susceptible to loosening torque from the flexing of the line. They also secure the line in a particular orientation.

I've always been concerned that aftermarket hydraulic trailer brake systems are underengineered and susceptible to all kinds of non-obvious sources of failure, flexing hoses beyond a safe bend radius, contact wear during suspension movement, and so on. Sure, if they're installed right by a tech who is aware of the pitfalls you can end up with a safe installation, but that's not much of a guarantee.

flynmike · 06-17-2013, 11:23 PM

I took my Airstream to a local garage I've had some experience with and trust to not screw my trailer up. They inspected the lines and the flare on the caliper that leaked and didn't find anything wrong. They tightened it up, filled and bled the system. $50 and all is well. In accordance with the Carlisle bleeding instructions I'm going to take it back after my trip next week and have them bleed the system again. The manager at the shop said the fitting might not have ever been tightened up properly and it finally worked loose enough to start leaking.

I'm going to add checking the brake fittings to my annual inspection.

Thanks for your responses...you gave me some stuff to think about and consider.

Mike

**Action** · 06-18-2013, 11:12 AM

Quote:

Originally Posted by flynmike

....... The manager at the shop said the fitting might not have ever been tightened up properly and it finally worked loose enough to start leaking.

I'm going to add checking the brake fittings to my annual inspection.

Mike

If the above scenario is correct AND the fittings have now been tightened correctly, they will never loosen up. Checking them will not hurrt anything and there are many things that can be checked. Lug nuts or lug bolts (depending on your trailer age) would be something that does loosen over time even when tightened correctly.

Glad there was no other damage or a single flare fitting used.

Now go camping.

>>>>>>>>>>>>>>Action

Skater · 06-18-2013, 11:49 AM

Quote:

Originally Posted by Jammer

I've always been concerned that aftermarket hydraulic trailer brake systems are underengineered and susceptible to all kinds of non-obvious sources of failure, flexing hoses beyond a safe bend radius, contact wear during suspension movement, and so on.

Are the hydraulic systems on trailers split into two zones as they are on cars?

ROBERTSUNRUS · 06-18-2013, 12:06 PM

Quote:

Originally Posted by Skater

Are the hydraulic systems on trailers split into two zones as they are on cars?

Hi, No.

**Action** · 06-18-2013, 01:26 PM

To expand on the above ... Typically it is no for hydraulic no matter what the actuation method. (There are several)

For electricly applied brakes the answer is sort of. If there is a failure of the wiring or brake at or near the individual wheel the system by design isolates that brake. If the wiring is defective closer to the front of the trailer at some place no braking signal would be delivered at all.

Best remedy for either system is a quick visual on areas that can be seen before dropping the shift lever into D.

>>>>>>>>>>>>>>Action