On Wed, 01 Jul 2009 08:34:09 -0400, Wizard of Woodstock
wrote:

Just a quick driveby - got some spare time this morning and I'd
thought I'd give a report on the brake actuator/solenoid problem on my
trailer. It's kind of long, but interesting.

The system that Ranger uses for the surge brake system is this:

http://www.ufpnet.com/Portals/0/PDFs/Actuators.PDF

If you scroll down, you will see a cutaway drawing - notice the two
pins at the top of the actuator. The right pin is the floater pin that
works the surge brake actuator, the rear pin holds the master cylinder
in place.

This whole system is held in place inside the trailer tongue by those
same pins - pretty neat system actually.

We already know about how the system failed - the brake solenoid went
south when it leaked, corroded and let go. What happened next was that
in the resultant slam/bang of stopping quickly, the shock absorber let
go, so that needed to be replaced. Investigating with UFP, I decided
to spend the $150 on the whole actuator system rather than try to
replace the shock absorber and brake release solenoid - to replace the
shock absorber and solenoid was going to cost $110 - seemed more cost
effective to go with a whole new system. However, I needed to get the
whole thing out of the trailer tongue.

Thus began the Battle of The Pins.

Removed the spring clips and washers - got out a five pound ball peen
hammer and a cold steel drift pin - pins didn't budge. After about
five minutes of whacking, I decided that was useless, so I sprayed the
pins down with PB Blaster,a good soaking, and left them for eight
hours to let PB Blaster work it's magic.

On the second try, the pins still didn't move - hmmm. Ok, got out the
twenty pound mawl and a chunk of hardened steel and really gave the
pins a whack or two - nothing - didn't budge. Got out the manual,
looked at the parts explosion - no spring pins holding anything in
place, two plastic bushings on the rear pin and two steel
bushings/rollers on the front pin. Ok, drastic measures are called
for but I wasn't going to use a heat wrench - I was concerned about
the trailer tongue as the pins were internal and I didn't want to heat
the galvanized steel up as much as would be needed.

Soaked it down with machine oil and let it sit for twelve hours - did
the mawl thing again, nada, zip, zero - no movement.

At this point, I gave up and took the whole thing down to my friends
shop to use his hydraulic press - figured that would be the best way
to do it - a little of hydraulic pressure might do the trick.

Well it did - but get this - the front pin took 18 tons - yes TONS -
of pressure to pop out. But a hell of a lot easier than whacking on
it. On to the rear pin.

I watched the pressure gauge on the press - it blew eight past 18
tons, flew by 25 tons, at 30 I was starting to get worried - this is
close to explosion territory.

37 tons of pressure - 74,000 pounds and it finally moved. Another
press at 20 and it moved halfway - another at 10 and it popped out -
hot as hell too I might add - almost as if it had been heated. :)

Get this - once the pin cooled down, I tried to push it though the
master cylinder - no problem. The only thing holding that pin in
place where the plastic bushings - which, despite the heat buildup in
the pin from the pressure, were perfectly round.

Plastic - hard to believe.

So onwards and upwards - new actuator arriving by Thursday and I hope
to be back in business with the trailer by Friday.

PS: Just in case I missed a spring pin or something, I called UFP,
described the problem and asked if there was anything I was missing -
nope. I asked if there was a way to move the pins or did they have
any suggestions.

Use a bigger hammer.

Gotta love it. :)

Hard to believe, but there's not much more fun in life than beating
something with a big f'ing hammer.
--
John H

"A government policy to rob Peter to pay Paul can be assured of the support of Paul."
-- George Bernard Shaw