P30 brake bleeding with TAG

circleD · March 22, 2014, 04:22 PM

I decided to flush my brake fluid since it was so dark of a brown it was almost black and didn't stop without putting the pedal to the floor. I don't remember the amount of ounces that I used but there are the little bottles of fluid and the tall bottles. I used 2 tall bottles and needed more for this so stock up when you get ready. To start with, the TAG axle is a separate system than the front and drive axle, it has it's own booster that is vacuum controlled in front of the rear drive axle and under the walk in door. (PIC1)
There is a separate reservoir and booster for the tag and it also needs to be done with the same bleeding procedure. There are post on here about HOW TO BLEED BRAKES so I'm not going into all of that. There is a bleeder screw up top between the HARD LINE and RESERVOIR that might need to be replaced ( I DID ) and the reservoir bowl was so rusty that I used an air compressor to blow some pieces of rust out of the bowl then put old fluid in there so I didn't waist any good stuff just so it would soften it up. I then drained the crud out of the bowl with the hand pump and refilled with fresh fluid. It took half of a tall bottle to get a decent color just from the reservoir to the bleeder 4" away because that part of the system has never been maintenance. The vacuum lines going to that booster are dry rotted and need replacing because this is causing my Vacuum Gauge to read 14-15 PSI. When you get that area cleaned up and repaired then you can bleed the TAG DRUM brakes like normal.
Now onto the CHEVROLET part of the brakes which include the front disc and "rear axle" disc brakes of the system which are HYDRO-BOOST that is ran off of the power steering pump and DAVE has a great post on that in the CHASSIS section, it is a must to read or download the manual for help!! On the rear axle you MIGHT be able to access the bleeder screw without taking the tires off but I figured to just take them off and do a maintenance check while I'm there and to have a piece of mind and found out I had to add air to the inside tire. I used a hand pump with wire ties to keep everything level where I wanted it so I could grab it quick and if the clear canister tilts towards the pump and gets in it, the suction isn't that great and you have to take it apart then clean it. (PIC2)
When I was ready to start I had my uncle watch the front reservoir under the gas pedal to make sure I didn't drain it because it gets really tiring to walk around these things. Once you get a vacuum and open the bleeder the fluid will come out and you can keep pumping the hand pump to keep the flow going as long as someone is filling the front reservoir " UNLIKE MY HELPER"

. It took the clear canister to fill up 3/4 full FOUR times before I could even notice a positive change. The amount in ounces, I don't know, but the Gatorade container is over 1/4 full on the ground of bad fluid and this part took almost a whole tall bottle to bleed and flush good. When I did the DS rear it wasn't as bad since the longest part had been cleaned out from the PS but still nasty.
On the front brakes I just laughed because I could simply leave the tires on and access the bleeders hoping to be done in 30 minutes. The front PS didn't have any fluid come out of it so I took the bleeder out and nothing. I tried the front DS and it bled quick and easy "since it is closer to the master cylinder". I went back to the PS and USING BRAKE LINE WRENCHS I started to take the closest connection apart at the frame where the hard line joins the rubber line at the A arm. I loosened it and fluid flowed right out of there so I tightened it back up knowing I have a collapsed line. Done some research and went to Advance Auto to get one but it would take a few hours till it got there so I went back to the camper to mess around with other stuff. I received the part and the banjo bolt had a stripped head so I went back to get a bolt so if you get new hoses, get new bolts and clamps also D:oH! .

Here are some tips and numbers if needed.
1. Clean and degrease the area prior to doing this so you can check for leaks and see what else needs to be repaired while you're under there. Plus spray the bleeders prior with penetrating oil.
2. Even though the hand pump is a 1 person job get someone to help because when you get the bleeder open and 1/4 turned let it flow and keep the reservoir full.
3. BUY new bleeders before starting and just replace the old ones. They make spring loaded ones and some with Teflon already on them. Keep the old ones as spares and wrap the new ones with some Teflon tape when installing them

.
4. Go to Lowe's or somewhere and buy 20' of plastic tubing for $7.00 because the tubing gets wet and hard to work with so use it then cut some more when needed. I'll get the size soon.
5. You can use gloves but they get slippery so just go bare handed and KEEP IT OFF THE PAINT!! it will eat it off.
6. Tools I used are a 10mm wrench/
Mighty Vac Hand Pump (use the tube from Lowe's with that kit)/
When ordering any part for a P30 make sure they order the stuff for a MOTOR HOME and not just a P30 or 1 ton van, the connections are different plus the P30MH part is made for 15,000 pounds and the others are not.
The part# for the PS rubber hose H38167 and DS is H38166 for the P30 MH chassis
The bolt that hooks the hose to the caliper ( Banjo Bolt ) is #13940
Get at least ONE gallon of brake fluid if you can to make sure you flush it all out even though it can take up 5 gallons when a garage does it.

DaveVA78Chieftain · March 22, 2014, 09:52 PM

Nice writeup

Took me a bit to understand

DS = Driver Side
PS = Passenger side

Hydroboost Article

Hydraulic Tag Axle Article

circleD · March 22, 2014, 09:56 PM

Thanks Dave! I hope this tid bit and your post will answer a lot of variable questions people might have.

TripleJ · March 23, 2014, 02:21 AM

whelp, I was gonna ask what the Teflon tape was for, because I've never really heard it used that way, but decided to Google it first. learn something new every day

circleD · March 23, 2014, 07:39 AM

I couldn't get a vacuum on one of the bleeder screws so I took it out and put some Teflon tape on the threads then no problem. Since you're getting the air out of the lines then go ahead and take the screws out and seal them with tape. It is worth the extra time

These older rigs need extra maintainance and up keep so plan a whole day for this.

DaveVA78Chieftain · March 23, 2014, 07:46 AM

Sucking air around the bleeding screw threads with a vacuum bleeder has always been a normal issue. The only concern I would have is I am not sure if the brake fluid will break down that plastic tape or not.

Dave

circleD · March 23, 2014, 07:49 AM

That's what I was thinking but I tried to keep it near the top and about 2 wraps.
Thank you "OZ" for fixing my pictures. I tried to outline it D:oH!

Oz · March 23, 2014, 03:38 PM

circleD · March 24, 2014, 10:55 PM

UPDATE. I've posted the same under Dave's post but I bled the power steering pump and have better brakes but not perfect. Added power steering fluid and had the front lifted by built in jacks

for this process. I'll bled the brakes AGAIN later to see if that helps. I disconnected the vacuum tube for the TAG booster at the motor and now I don't loose vacuum when I apply the brake. So read the manual and take every tip you can before doing brake work. I hope this helps.

Stripe · March 24, 2014, 11:21 PM

aren't those jacks the bees knees??

I use them to lift, but not to hold. Put jackstands or blocks under there..

circleD · March 24, 2014, 11:29 PM

Yea I just use them to raise also then support with stands. But I love having BUILT IN LIFTS

. Because its one of the few things that still works. Brakes got better today then the alternator stopped so I'm bragging while it works

ClydesdaleKevin · March 25, 2014, 12:02 AM

Am I missing something? We have the Mor/Ryde suspension with a tag axle. Is there another brake fluid reservoir hidden somewhere I'm supposed to check?

Kev

Froggy1936 · March 25, 2014, 01:12 AM

Kev Does your Tag have brakes ? Frank If so other pics looked like resivour was near power brake servo .

DaveVA78Chieftain · March 25, 2014, 09:21 AM

Oh Kevin,

If your tag axle has brakes included then Hydraulic Tag Axle Article

There are some rigs that used electric tag breaks which means there is a brake controller hidden somewhere.

Dave

ClydesdaleKevin · March 25, 2014, 10:22 PM

All I know is that the Mor/Ryde folks told me that the rear tag axle brakes work off a proportioning valve setup from the main system, an unobtainable part if it ever goes bad, and that if it DOES go bad, they have an electric brake setup to replace it with in that event. They still work great. Just making sure there wasn't another reservoir I didn't know I was supposed to check! I check everything before every trip!

Kev

circleD · March 25, 2014, 11:25 PM

Just the one in front and the one at the tandems. That's what the picture is of and the valve in question is on the front of the vacuum booster. If you look at the first pic it will be to the right of the booster.

DaveVA78Chieftain · March 26, 2014, 01:31 PM

Kevin: To know for sure, just follow the tag brake line back to where connects to the main system.

BrandonMc · July 22, 2016, 12:01 AM

I really like the writeup.

Currently, I have no assistant to pour, so I estimate amount in the master cylinder after drawing with pump and pour, repeat.

How do you think the best way top get at that brake fitting to wrench on it would be? I can barely get my hand in there. Must I take the tire off to allow the suspension to be out of the way? I can barely get my fingers in there. Seems like only a 90deg fitting for the bleeder will this work. HAs anyone tried this with success?

https://www.amazon.com/Lisle-10900-Brake-Bleeder-Wrench/dp/B000CO87ZE

Rickf1985 · July 22, 2016, 11:01 AM

I have several of those wrenches, only one is in that shape. The rest I have heated and bent to new shapes to fit whatever I was working on at the time. I would say I have at least 25 modified wrenches and brake spoons for doing brake work. And that is in addition to the ones that are not modified. There are a LOT of times that a standard wrench is just not going to fit and you have to improvise.

I have a whole tool box dedicated to Frankentools, tools that have been cut, bent, welded to each other or assorted pieces of metal to make them reach into impossible places. There are probably over a hundred tools in that box and not one of them is unmolested but all are usable for something, somewhere that is impossible to get with a standard of the shelf tool.

BrandonMc · July 22, 2016, 03:01 PM

Yeah, I'm thinking I need to grind one of my extras down a little, and go from there. So it can be done is what you're saying.

Rickf1985 · July 22, 2016, 04:53 PM

Well, I have never done an older Winnebago but I had a garage and I never had a vehicle that I could not get a wrench on the bleeders or lines. That is where all the oddball made up wrenches came from. Don't get me wrong, sometimes it is just plain easier to take the tires off. Can you get a wrench in there? Maybe, if you turn into a pretzel and bend the wrench 29 different ways. But if you take the tires off and the wrench fits right on then you tell me, which is easier? I got paid by the hour so if it takes me ten minutes to get the tires off and a wrench fits right on then that is the route I am taking. Keep the customer happy and they will come back. (plus it is a lot easier on the old back)

I just noticed you have an 88, I am assuming you have disc brakes and the issue is the bleeder inside the wheel and the wrench hits the springs? The easiest solution is going to be remove the tires. Even if you make up a wrench you just do not have the swing you need. It is a good time to check the pads and lube the slides.

BrandonMc · August 07, 2016, 02:51 PM

1988 Winnebago Chieftain P30 Chassis

I had success bleeding the brakes myself, matter of fact a full flush of what must have been the original fluid and without taking the rear wheels off. This is what I ended up doing, and it's to help someone in a similar situation like myself....

Took this tool, and used a dremel to cut the 10mm side off, and then opened up the wrench on the 8mm side so it was open to engage the bleeder screw. It would be ideal to also bend the wrench if possible to the angle shown in the front view below the top view.
Performance Tool W80620 Offset Brake Bleeder Wrench

And then I purchased this unit with the resevior bottle to do a reverse brake bleed job.
Phoenix Systems (2005-B) Bench Brake Bleeder Kit, One Person Bleeder, Fits All Makes and ModelsPhoenix Systems 7002-B One-Man Brake Bleeder Capture Bottle With Quick Adapter

The 90deg fitting worked great, and I could do the entire line without getting off my back undernreath the chassis and fill the master cylinder, reverse brake bleeding eliminates the need to make sure the master cylinder is drawing fluid, because you reverse bleed the system.

So now I have this tool, and likely saved money on the whole deal. Took a lot of toil and trouble to figure this stuff out, it was still difficult, but much more manageable. I cant tell you how nice that little fill bottle is, check out the video if this is still not understandable.
https://www.youtube.com/watch?v=FB8kzUEqK3U

Rickf1985 · August 07, 2016, 07:21 PM

The problem with reverse bleeding is that air rises to the surface, the bleed screw is on top, if you are adding fluid to the bleed screw and the brake line is lower than the bleed screw how is the air in the caliper going to bleed out? It isn't, the fluid you add will just go around the air and right out the brake line leaving the air behind. Then you will need to vacuum bleed it to get the air out. Seems like a lot of extra work. Just vacuum bleed it to begin with. I prefer not to push the dirty fluid back into the master cylinder valves and pistons also.

It does look like a handy tool though.

BrandonMc · August 08, 2016, 11:30 AM

hmm, I believe this is the intended effect as advertised. Since the lines are lower than the master cylinder, the air naturally rises instead of resisting being pushed down and out doing it the traditional way.

circleD · August 16, 2016, 10:00 PM

I'm all about making easier. I tried to do it with the tires on but I didn't feel like I could do a good job. I think that wrench you modified would make it easier if you had someone helping you pushing the pedal. I didn't have any help either and used that hand vacuum pump and got out the dark fluid. Just remember that your life and anyone riding with you depends on your work.