Drum brakes on my lovely pa-22-Colt.
Hi every one.
I have a question about your experience with the drum brakes fittet original on some Pa-22's.
I like the layout of the system, and the drumbrakes look good inside, and they are not at all worn, or anything. But the braking function is generally very poor. I know that many have fittet dics on the main wheels. Is this the only bullit proof solution?. Actually I like the drums very much. There is no air in the system - we have checked this. Apparently everything works as planned - However not very effective.
Any suggestions. ? thanks in advance
Morten Munkesoe / Copenhagen - Denmark
Morten, Are your brake shoes adjusted correctly? There is an eccentric adjustment for the brake shoes. I lift the wheel off the ground and spin the wheel while turning the adjustment until it drags and then back it off a touch and lock it down. My wife's Tri-Pacer has drum brakes and they work well. She doesn't get real aggresive with them but they will stop the airplane with no problem.
It would be nice to stay in place doing a runup, other than that my drums are ok for a tricycle gear. There is a booster for the master cylinder. Considering that but first I think I'm going to replace the 50 year old linings. If anybody ever replaced them they didn't put it in the logs. I figure some new material ought to be a little softer and more effective. My plan is to take them to a local brake shop and tell them they are off a old motorcycle. You know how some people get when you mention airplane, the price doubles. We put discs and 700x6 tires on our 20.
Coulda' sworn I read somewhere that all Colt's came with disc brakes. I take it that is not the case?
According to the Type Certificate, disc brakes are eligible on all PA22-108s but the parts manual shows them starting on serial number 22-8270 and ten other serial numbers until serial number 22-8457 and up which all had the disc brakes.
Two Main Wheel-Brake Assemblies, 6.00-6, Type III
(a) Cleveland Aircraft Products, Model 20-6 (Model PA-22-108 only)
Wheel Assembly No. 40-28
Brake Assembly No. 30-18
Just as a side note, our vented booster brake is approved to use on the Tri-Pacer with either the drum or the disk brakes. More than doubles the braking pressure of the original Scott diaphragm.
Thanks for your advice.
The booster unit sounds interesting, Where is this item available. ?
For your information our plane has serialnumber #22-8284, and OY-AFT was the first Colt arriving in Denmark in 1961. There are currently 4 airworthy Colts in the country.
By the way, we have already started planning OY-AFT's birthday party in 2011. The lady becomes 50 years old on the 7th. of July.
I do not know of which booster you are referring too, but the only way you can get ours is directly due to the export requirements. I see you are in Denmark, I am a DMIR and can fill out an Export Airworthiness Approval 8130-3 form for our product.
Our booster works best with the disk brakes. It is approved to work with the drums but you have to have the wheel brakes adjusted right to work properly and there can be no air in the system. Tri-Pacer brakes are a PITA to bleed all the air out of IMHO.
Brian - I am in the process of my annual inspection and pulled apart my master brake cylinder to clean all the years of non maintenance out. Diaphram and plunger look just fine to me. I have the drum brakes on my Tri-pacer. I'm finding the bleeding of the brakes is exactly a pain in the arse...as you mentioned. Is there a way to bleed them backwards? I know this works real good on most brake systems to really get all the air out. However, with the tripacer, I can't figure out how to make a threaded adaptor to put in place of the screw to put my hydraulic can and clear tubing on effectively. (sure wish there was a bleed valve...) Short of drilling the center of a screw out....any ideas on bleeding those brakes?
I have done it both ways....have a drilled out screw in the tool box specificaly to hook up the bleeder for the drums. Have also hooked up a pressure line to the master and opened up the wheel bleeder.
They are the single most pain in the rear to get all the air out.