Do the 'bump" wreck your brake cylinder

[1st Sail]

Looks like the repeated 'Mac Bump' has taken out my brake cylinder. After cleaning I backed the boat into the warehouse without the trailer lights plugged into the Yukon. Normally you can't back up a foot without the lights plugged in to activate the solenoid. I didn't think about it until I unhitched and realized it was not plugged in. The goose neck was fully compressed in the rear position.
This weekend on the way to the launch (in the city 1.5mi. ) the hitch would clunk when I pulled out from a stop. So there is no compression resistance what so ever and I presume no brakes either.
Where do you find replacement cylinder, parts or repair manual?

Thankd to all for the help.

Dave

[rwmiller56]

Dave,
You have to determine the manufacturer and model number of your brake actuator. It might be stamped on the actuator.
I was lucky when I bought my boat, as the PO had all the manuals for the trailer actuator, bearing buddies and disc brakes.

On the trailer for my 2005 26M, it is a UFP A-60, but without a brake lockout solenoid.
http://www.dhmtrailers.com/online/home.php?cat=7

Good luck.

Roger

[dennisneal]

Dave,

I don't understand you assertion that doing the "Mac Bump" ruined your brake cylinder. I've done the "Mac Bump" many times and my brake cylinders don't leak, on either my truck, or trailer. I'd look for another cause, but, in my experience, the cause cannot be determined.

Dennis

[Sumner]

You have probably done this, but is there fluid in the master cylinder. If not it just might of gotten low, but if not you have a leak somewhere and it might not be the master cylinder,

Sum

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[1st Sail]

Thanks for the input. The master cyliner reservoir is topped off. There are no visible signs of a leak so I would assume the seals are blown due to the sudden stopping and the brake fluid is blowing by the seals back to the cylinder. A very slow soft stop will cause the goose neck to compress fully as if there is no resistance from the bake cylinder. The pads and rotors are very low miles and minimal wear.

[pokerrick1]

I suspect your problem is an anomoly (sic) but I'd like to hear if others think like you

Rick Less

PS I wish Mike Inmon would chime in on this and give us his opinion.

[The Mutt]

Have you bleed the break line, might have air or blockage.

Glenn

[Boblee]

All of the above advice especially bleed the brakes to see where it is leaking, do not think it will be seals and definitely not caused by the bump.

[Paul S]

Chances are it is leaking in the tounge. There is no gromet where the brake line exits the tounge.. and it can hold water..so the line is probably bad.

Until you take it apart and properly diagnose it.. it is hard to tell if the master is blown or it is a brake line (or caliper, etc)

Doing the mac-bump is no different than doing hard braking while driving.

Probably need a brake line would be my guess.. Of course the master could be blown. Wouldn't be the first. But it would have nothing to do with the mac-bump. if it was going to fail.. doing the bump or not would not change its outcome.

[waternwaves]

having replaced those cylinders on several trailers.......

the normal failure is post low fluid level, hard braking after that will bottom out the cylinder, continued hard braking after that bends things and puts metal on metal, especially backing up or backing up hill and turning,

relatively easy to repair tho. I got my kits from champion trailer

[Paul S]

having replaced those cylinders on several trailers.......

the normal failure is post low fluid level, hard braking after that will bottom out the cylinder, continued hard braking after that bends things and puts metal on metal, especially backing up or backing up hill and turning,

relatively easy to repair tho. I got my kits from champion trailer

true but got to remember to fix the problem not the symptom. If there is a bad brake line causing the low fluid, replacing the master will be futile..as it will fail soon after.

If the master is bad. replace the brake line 'while you are there'. Cost less than $20 extra

The brake system is a closed system, it should never get a very low fluid level without a leak. FInd/fix the leak first!

[1st Sail]

I contacted MacGregor they referred me to Universal Functional Products. You can access manuals for their product line at http://www.ufpnet.com.

Here is the manual pdf for the A-60 which is on my ’06 trailer: http://ufpnet.com/Portals/0/PDFs/A-60,% ... enance.pdf

In the event you need a replacement Bass Pro listed the A-60 in their inventory http://www.basscatstore.com/a60hydrauli ... uator.aspx

I will keep you posted on the results of my repair.

[Paul S]

get a brake line too!! That is more likely to fail than the master. Plus you will most likely rip the line when you try and remove the rusty line from the master as well.

[Catigale]

The brake system is a closed system, it should never get a very low fluid level without a leak. FInd/fix the leak first!

Someone posted here that they thought their brake fluid evaporated one summer. Ive never heard such a thing, and the chemistry of this fluid makes this pretty unlikely imho. I agree that if your are topping off your master cylinder more than once a year, you have a leak.

[1st Sail]

My UFP A-60 replacement arrived today so I will keep you posted. After contacting several midwest suppliers and UFP I never really got a definitive opinion. Cost for parts are approx. 1/3 to 1/2 the cost of a new unit. Rather than going with out the trailer for a week + I opted for the replacement unit. I still plan to disassemble the old one and find what failed. As you know you cannot see the unit with out removing from the tongue channel. FYI there are only 2 components that effect breaking under normal driving conditions, master cylinder and back up solenoid. There is a rebound shock that decompress the A-60 after breaking to minimize the sudden extension of the A-60 after stopping or decelerating. This has no effect on actual stopping. In my case if you recall I had no fluid leaks, reservoir was on spec, but no breaking while under tow or backing up with the electrical unplugged from the Yukon. I expect to either find blown master cylinder seals or a solenoid stuck in the by pass position.

I'll post late Sat or Sun after I replace with the new. I plan to do a brake line bleed first in the event the reservoir sloshed when doing the mac bump and inhaled air into the master cylinder. Doesn't seem likely but I want to review all possible issues. I was supprised how small the shock and master cylinder are in actual size.