Replacement Push Rod Kit for Atwood 82541

Video Transcript for This Old Boat Trailer: Master Cylinder Installation

Today on This Old Boat Trailer we are going to rebuild the hydraulic actuator on here and we are going to be using part number 85841, the master cylinder itself, and then we are going to use a master cylinder replacement cap part number A87478, and the cable push rod replacement kit part number 85852, all from Atwood. The first thing we need to do is remove the old master cylinder itself. This is going to require taking off the cap which we have already done. We have disconnected the line back here already and then we can see our factory line, lets disconnect that and then we are just going to undo these four bolts right here. There is probably going to be some leftover brake fluid in there so it will be a good idea to wear some gloves or something. We are going to pull out the back and then underneath there is a little push rod you may want to pull away from it too to help knock it out. 01:09

The gasket for your old master cylinder sits on the bottom here. Most of the it came off with the old master cylinder but it is a good idea to run a scraper over it to make sure you get all of the junk out of there. Now we have got the master cylinder out, lets check the condition of the shock absorbents on the inside of here. Basically you should be able to move it but you should not be able to move the fast. It should be a slow, even, steady pace like this. In this case I think the shock is in good shape so we will not worry about replacing that. The next thing we are going to do is remove the old push rod part right here. We are going to have to take apart this bolt and the nut on the other side. Take it apart and get this out. Remove the bolt. There is a little spacer on the other side and hang on to that. This will come forward and the block, you will want to save that too and this part will get replaced. Lets pull the rest of that cable out from the top and down and lets go get our new parts. 02:28

First we are going to reinstall a new push rod cable. Push it back up the original opening and push that into place. Put the block in. We have got a few pieces to line up here get the location and run the bolt back in. Once you have got it through put the spacer back in to place and then reinstall the nut. We will use one of the new placement lock nuts on the outside and then we will tighten it back down. You do not have to crank it, just get it snug. This is our new master cylinder. We installed a little angle piece for the line to go into. On top we already installed the gasket which is kind of neat. We spent some time cleaning off the top of it so it adhered good because the gasket itself is basically like a sticker. What you also need to do is add a little rubber boot right here and that is going to slide on over the metal and it has its own little pocket that it goes in to. What will happen is that this push rod will end up going inside of here. If we can we will try to push everything up inside there and work it into place. One quick look and make sure it is all lined up and we will install the new bolts that came with the kit to hold everything in place. When you tighten these down you just want to get them snug, we do not really have to torque them down or anything. The next thing we are going to do is work on our catch for our cable. This one is in pretty decent condition but we will replace it. We are going to grind off the top of the rivet and to keep the sparks and junk and shavings from flying into the master cylinder we are going to put a paper towel in there just to plug it up to keep stuff from flying in. We are going to try to punch this out to see if we can get anywhere. If not we can grind it down and punch it some more. The next thing we need to do is remove the bolt for our shock right here so that way we can just push it out of the way and have plenty of room to install the nut and bolt. If you can not get this nut removed it might be easier to open up the master cylinder once again and then just put your hardware in and reassemble it. Put the tab into place and then we will sneak the nut underneath and run a new bolt through. Now we will tighten the master cylinder back up again. 05:24

Lets turn our attention to the other end of the cable now. We will put our hook on here and we are going to take a pair of channel locks and squeeze it down. Back to our master cylinder lets hook up a line going out to the trailer brakes. We will run it up until it stops. Maybe about 1/ 8 of a turn more and that should snug it up just fine. We are going to turn our attention to the hydraulic lines at the slave cylinders right at the hubs. We are going to disconnect the lines. We are going to put a cap on one end and then a line on the other so that way we can use a master cylinder to flush out the old fluid and get new fluid in there. It would be just like bleeding the brakes except we will be removing old fluid. We will fill up the master cylinder and we will pump fluid through. All we have got to do really is just move the hydraulic actuator in and out a few times to get things going. To make it easier put vise grips on the end here to give it more leverage. Draw in some more and that will push out fluid out back. We will repeat the same process from both sides of the lines. Next we will reconnect our lines to the slave cylinders in the hubs and then we will bleed the slave cylinders again and we should be good to go. We are going to do the other side. We can start them and then we will tighten them down with a wrench. Now we can start bleeding the slave cylinders. We are going to take the bleeder valve and open it up and we are going to slide a rubber hose over that and run it into our container. Then we will bleed the brakes. This will take two people to do. One to activate the coupler itself and one to shut the valve when you have gone through the stroke and it stops. We have got some fluid in the bottom of our container here. We want to keep running fluid until we get all of the bubbles to come out. This will take quite a while to do too. We will repeat the same process on both sides of the axle. When we are finally done we can install the cap and then we will be finished. With that, that will finish it for This Old Boat Trailer using part number 85841, part number A87478, and part number 85852.