Bonanza Retractable Step Details (by Beech Lister
The "frangible" link shown above is Beech PN: 35-410434
Here are Doug's detailed pictures and descriptions of the
Beech retractable step design below
Close up on the connection to the nose strut (note the dog bone shaped frangible
link). This link is designed to break should something bind in the step
retract system so the gear can come down. The cable has a swaged ball end
that connects to the frangible link with an SA 362 fork end (partially covered
by the black tube) and clevis pins secured with cotter pins. The black tube is shrink tube
and keeps the cable from getting tangled on the nose gear and ruining your
day. I believe the addition of this piece was a Service Bulletin years
Cable: 1/16 dia. 7 X 7 strand stainless
steel or galvanized steel control cable, 14 ft. long. (This will
allow at least 6 in. extra length.)
Either a MS20664C-2 ball with single shank or
a MS20663C-2 ball with double shank is to be swaged on one end of the cable,
( For 13 cents more, I prefer the double
shank ball as there is more swage length. Either will fit into the fork
end swivel fitting.)
The 1/16 fork end swivel fitting is SA
362-2. ( Old one reusable if in good condition.)
The swivel fitting is attached to the safety link and the safety link to the
nose gear with flat head clevis pins AN393-7, cotter pins AN380-2-2 and
See Aircraft Spruce possible cable candidate HERE.
The cable goes from the nose strut over a pulley mounted to the bulkhead in the
The pulley rides on the bolt shown in the aluminum bent in the
deep "U" shape. There is a pin (secured with a cotter pin)
forward and above the pulley to keep the cable in the pulley groove. Be
sure the cable is UNDER the pin. When
replacing the cable it is a good idea to remove and check the pulley (AN210-1A) in the nose well at the same time.
On the other side of the pulley (and bulkhead), the cable goes into the
housing. Be sure it goes in square to prevent chafing and eventual cable
failure. This is where the cable is fed through to the back. This is
one case where you can actually push a rope (if only a few inches at a
time). I have found that tinning the
end of the cable without the ball with a large soldering iron and filing it to a point is helpful in getting
it to slide smoothly into the housing. It also keeps the strands of the
cable together at the end. If the housing has years of oily goop in it,
you will have a tougher time. If that is the case, you will have to pull
up the floorboards to remove the cable housing <no grin>. If your
airplane is one that does not have a continuous housing you WILL have to pull up
The cable comes out of the housing behind the bulkhead and parallel with the
step. The step has two rollers that fit in the "U" shaped
channels that act as the stops to keep the step from coming completely out (this
one is not all the way extended). You can see the cable coming up through
the "L" bracket and then between the clamping pieces. The bolt
has a hole in it to allow the cable to pass through. My understanding is
that this hole is a feature added to the kit by the owner <wink>.
These are the springs that are part of a Beech kit to
eliminate the bungees that eventually fail and dent the fuselage in the upper
right corner. If you don't want to pay Beech prices, the springs are most
likely available at the A/N section of Home Depot where they have springs for
Thanks Doug! That was an
awesome write up of the retractable Bonanza Step Cable.
Here is a narrative from Bonanza Owner Larry G. that
describes how he replaced his step cable:
I broke a boarding step-extension cable a few
years ago. I went to a local business, Delta Cable, and had a new cable made. It
was nothing more than 1/16" twisted-strands steel cable with a ball swaged onto
the end. I got stainless. I got it way too long on purpose. I tinned the "bare"
end with solder to keep loose strands from catching in the cable housing as I
fed it through. Starting from the nose gear tunnel, feed the tinned end over the
little pulley and into the end of the cable housing. It's pretty much a straight
run to the where the cable housing goes past the rear cabin bulkhead. That's
where the "inner" cable caught and would not go the final 7 or 8 inches because
the housing bends upward. I removed the aft end of the cable housing from its
attach point so I could lay it our flat toward the tail cone. Yes! The cable
went the rest of the way through. Reattach the aft cable housing end.
Figure out a way to hold the step extended. I
cut a full length slice out of an 11" long piece of 2" inside diameter ABS
plastic pipe (leaving a C-shaped section when looked at from the end of the
pipe). Pull the step out and slip the pipe over the shaft of the step. I cut the
pipe a little short, so I could adjust step extension with shims (electrical
tape over the end of the pipe). Secure the forward end of the cable to the nose
gear leg (don't forget the shear link!!!). The attach point is a lug held onto
the nose strut with a nut. I think it's easier to assemble the cable end & shear
link hardware to the attach lug, and THEN poke the attach lug through the gear
leg and install the nut on the lug's threaded end.
Loosely attach the aft end so that, with the
gear down, the step is almost totally extended. You want about 1/8" to 1/4" of
extension travel level left when the step is extended. Enough that the cable is
held in tension by the step retraction springs only - not stretched because the
step is all the way down before the nose gear is all the way down. But, don't
leave enough margin that the step moves too much when you step on it. I can see
someone put their weight on the step and suddenly it extends another inch. The
person's foot could easily slip off the step and their skull dent your flap and
bloody the ramp.
As I said, I did this a few years ago. Then
last week, during a gear swing while on one of Linn Kastan's awesome Beech
jacks, the swage failed and the step sprung to the retracted position. Startled
the crap out of me. I figured the shear link had broken, but it was intact. I
found the swage ball on the floor. The guy at Delta Cable took a look at it and
said that whoever did the swage, didn't crush the ball on well enough.
Unfortunately, the forward end of the cable
went into the end of the housing and I could not pull it through to attach a new
ball (which would have been difficult, anyway, with the cable still in the
airplane. The end where the ball had been also unraveled a little, making it
hard to pull the cable out from the aft end. But, I pulled harder and it came
Delta Cable made me a new cable. $6.31,
including a better swaged end. I will install it next week. If you need, I will
take some pictures of the attach points in case you have difficulty figuring out
how the thing attaches. The front end is pretty easy to figure out. The back end
is odd because the 2 springs do not attach to the same pieces of hardware on
When you have a cable made up, anything larger
than 1/16" won't fit in the housing and the next size smaller (3/64") might not
be strong enough.
If you can't feed the cable through the
housing, you're somewhat screwed. Getting to the old housing to remove &
replace has got to be a total PITA. It runs along the belly under seats & floor
boards and goes through access holes in the spar boxes. It goes under the
aileron cable system. I was hugely relieved when I was able to thread the new
cable through the old housing.
Here's a pirep from retractable Bonanza step owner Al D.,
on his cable woes:
I felt a slight fray once so for the last few annuals I've
been watching the step cable. With the recent thread about the step cable being
brought up, I figured now is as good a time as any, so out she came. If you take
a look at the pic you'll see a number of frays pointed out and the tape on top
shows the distance from the front end, where it's swedged. Probably the 4
closest (15-18) were at the pulley when the gear is extended. The 11.5 may be
when the gear is retracted and the 24.5 was definitely inside the housing!
For S's & G's I called for a price and they were about $110,
waaaay too much for $7 worth of parts, so I'll have a cable place make one up
for me and let my IA determine if it's airworthy, or stepworthy if you prefer.
After measuring, 14 feet is plenty long. The swedge is the important part of the
Thanks for the pirep on the length Al!
Here is a pirep from Robert M. on his cable replacement sourcing:
replaced my step cable several years ago and it's been working
flawlessly since. I just checked my notes, and it says I purchased 17 ft
of 1/16 inch 7X7 stainless steel cable. Spruce P/N is 05-03500.
If you match up the cable size to the housing size, you should be good to go. I recall it being about 1/4 OD.
Good luck, nothing on these old birds is more satisfying than a retractable step that works properly. IMO"
Here is some additional info on the frangible link of this retractable step
system which is designed to break if the stress on the cable is too high:
35-410273 LINK, STEP TO NOSE WHEEL CABLE SHEAR
The March 2006 ABS archive says that particular part goes to G-35 and earlier
models, and it turns right around and says part #35-410434 goes for H-35 and
later. According to the article, "They are the same except the 434 is (.375)
wide through the full length, not necked down as the 273 link shows".
Doug's C Model Bonanza earned him a Lindy! Way to go Doug!
Here are some pictures of Beech Kit 35-4003
from Adam M. that consists of the springs and attaching hardware.
Download them to get good resolution of the
dimensions & PNs.
Adam did a rough test with the NOS springs. Per Adam: "The
springs have about 19 to 20 lbs. of tension when extended in the mounted
position. This will not be exact as it was done with a measurement outside of
the airplane but will be close. For reference the screen door springs I
purchased were 3" longer and only had about 8.5lbs of tension at the same