weekend warriors-rear brakes

[87MH]

Originally Posted by swebster

......One question: do you think your dragging brakes contributed to your mileage issues earlier in the year?

Good question - I really don't think so. One of the reasons I say that is because I am so anal about keeping records. With the records I hope to identify an anomaly as soon as possible….if I detect a small problem hopefully I can fix it before it becomes a big problem.

Partially attributable to this personality trait (anality), I have gotten into the habit of doing a walk around on all of the vehicles whenever I do a fuel stop……look for dings, check the tires for wear, look for a low tire….and so on.

The additional things I do after looking at each tire is I put my hand on the tire – check for high temp, then I put my hand on the middle of the rim and then on the hub – at least I can tell the difference between 120° (OK), and 150° (too hot). The tire temp lets me know if the tire pressure is OK, the middle of the rim checks for a dragging brake, and the hub lets me know if a bearing failure is imminent.

I am so anal about doing this (especially on the MoHo) that I purchased an “infra red remote thermometer” (with laser aiming assist ) which lives behind the driver’s seat. I grab it on my way out of the door when stopping for fuel.

So…to answer your question about the one really low fuel mileage I encountered, I think (hope) I would have picked up a high temp. Besides, this brake would have had to have been dragging for a long while since then (had it been a continuous problem I KNOW I would have noticed it (a high temp) somewhere along the line).

On the trip to Missouri in May I “did” about 20 miles of typical Missouri gravel roads – I could have picked up a piece of gravel in the pad and shattered it.

Lots of possibilities as to the cause – too bad I can’t be “for sure” on one and lay that problem to rest.

The good thing is, because my friends brought the “metal to metal” sound to my attention, I am fixing a relatively small problem before it grew into a huge problem.

This whole thing reaffirms my “maintenance” philosophy – do regular inspections, be “aware” of the vehicle, and don’t ignore ANY indication of an abnormality.

[swebster]

I purchased an “infra red remote thermometer” (with laser aiming assist )

I think that must be an option available only on "Texas" models. Do you have a "rack" for it on the MoHo?

I am reminded of a time about 12 years go when my wife and I broke down in Badlands National Park in our 79 Mercedes 280SE. We flagged down a park ranger who called in for a flatbed. The driver picked us up and towed us to "town" (Interior SD). The whole way down the road he kept fiddling with things in the truck..hitting the brakes, look at gauges, etc.

When we pulled into his garage the drive wheels were billowing smoke. He had left the emergency brake on the whole way down. I'm sure a little longer would have resulted in a fire. So here was a guy who drove a tow truck, was a mechanic and owned the garage who didn't make the connection. Needless to say he was one very upset guy as the parts man only came on Tuesdays and it was Weds.

At least you found the problem and can fix it in your driveway rather than on a trip or in the mountains. Yikes!

Please keep up the pics. My MoHo seems to follow yours for repairs within a few months and the pics are a great reference.

[ALANSD]

Dennis- and I thought I was obsessive! Glad to hear that many of you are worse!
I also thank you for the posts. I don't yet need brakes, but its just a matter of time I'm sure, and you can bet I will be greasy for a few days as well.

Meanwhile I was thinking I would have the brake fluid extracted at a local brake shop and replaced, while I am doing my fall maintenance...hoses, oil change,new coolant,etc.

Also I am so thankful that over the past year + and many trips, I have had no breakdowns. Other than the tiniest pinhole hose leak, all has been well for quite a few thousand miles. It just shows how the maintenance and the advice I gleaned here has made my experience that much more enjoyable.

[87MH]

Thought I'd post a few pics of the (very slow) progress.

The first is a shot of the new hoses and the old ones. The new ones were made by a local Hot Rod/Hydraulic shop local to West Houston. The price per hose for the custom made was about that of the usual suppliers (NAPA, Pep Boys, O'Reily's, Auto Zone) so I went with the custom, eliminating the possibility of an "almost right" hose being shipped. Cost of the hoses were $190, bringing the "parts" total for the brake job to $620.

I learned that there are a BUNCH of possible hose end terminations. The Hydraulic shop had to cut off and reuse 4 of the end terminations - the weld job is such that you can't tell the new from the old.

The second shot is that of the old hose on the Driver Front Control Arms.

Third shot is a Macro of one of the front pads - all of the front pads look brand new. Interesting observance here - the driver side rear pad (outside pad) is ALMOST ready to self destruct. (Remember, it was the curb side (outside pad) failure that caused the curb side rotor to be replaced.) Both of the rear inside pads were at about 50 % left......and the brake wear indicators are on the INSIDE pads - neither of the wear indicators were about to "squeal", yet both of the outside pads were either failed or about to! -- Again, front pads look new.

Fourth pic is the windage shield on the driver's side of the engine - that will have to come off to access the master cylinder.

Pic #5 shows one of the ways the Texas MoHO 'Streamers keep their Laser Thermo-Pistols handy.

[ALANSD]

still the cleanest undercarriage area I have seen. Makes me want to steam mine and repaint it.

[PeterH-350LE]

Originally Posted by 87MH

.........

Pic #5 shows one of the ways the Texas MoHO 'Streamers keep their Laser Thermo-Pistols handy.

Too funny........

[87MH]

Quote by Alansd: .....makes me want to steam mine and repaint it.

Only if you spend no time with family, have no semblance of a live (as in "get a") and REALLY enjoy at lot of time on your back in cramped quarters in 95 + degree weather.......but it does beat therapy.


Rear curb side hub and rotor pulled, caliper stud bolt retightened, and hub reinstalled and torqued. Installed rear brake lines (DOT approved Stainless wrapped teflon covered in clear plastic). Installed both rebuilt rear calipers with new brake pads. Front brake lines are also new. Front pads appear to have 80% + left - driver side rear outboard caliper (the one WITHOUT the squeal wear indicator) had less than 1/8" remaining.

Pulled the windage tray and removed the old master cylinder - memo to anyone trying this themselves - the (front) support that goes from the master cylinder to the frame HAS TO BE REMOVED for the master cylinder removal. Remove rearmost brake line connection first, then forward brake line, then cylinder/frame support bolts, THEN the master cylinder can be removed.

I purchased a good set of "Flare nut wrenches" prior to starting this job - would not want to try to do the brakelines without them.

The older and fatter I get, the more I am concerned about safety.
Pics below are the jackstand setup for total tire removal.

Front shot is a pair of 6 ton rated jacks to the frame.

Rear shot is a pair of 6 ton jacks to the frame behind the tag axle.

Rear also shows a pair of 3 1/2 ton jacks under the drive axle.

Hydraulic levelers left down with some pressure on them.

The frame/monocoque structure flexes so much that if the rear levelers take out more than a couple of inches of suspension movement the door binds up to the point that it will not close - so I try to support the rear when I know it will be laid up for a long period of time.

[overlander63]

Dennis, one thing I would have replaced with the caliper hanging on one side only, and you may have, and I didn't see it listed, is the hold-down bolts and the metal slides for them that go in the calipers. If they are bad, or worn, rusted, whatever, they will cause the brakes to wear like you have described. Parts are cheap, and you may even be able to replace them without pulling the wheels back off, as the parts are on the inside edge where you can possibly access from under the MH.
Good luck finishing up.
Terry

[87MH]

Originally Posted by argosy20

....one thing I would have replaced with the caliper ....... is the hold-down bolts and the metal slides

Thanks for the heads up....bolt and slide spring were part of the caliper "kits" as were new copper gaskets for the brake line interface. All of the parts were in good shape (except the rotor and pads), and everything that slides received a coating of a special brake parts lube - similar to never-sieze, but made specifically for brake slide/contact areas.

Picture #1 below shows the new master cylinder in place - also purchased a "vacuum kit" to bleed the master cylinder, lines, and calipers - 40 bucks very well spent. Besides the master cylinder, also note the support from the MC bolts to the frame - this has to come off as outlined earlier. One of the new brake hoses is visible at the lower left hand corner.

Picture #2 shows part of the "while your at it" scope of work expansion....ran cold compression numbers while I had every thing apart......not too bad considering 80,000 miles, lugging around 8 tons, and turning over 3,000 rpm at 60 mph.....150 to 170 psi. The plugs (platinum points) had about 8,000 miles on them, and really needed to be replaced. The electrodes were very rounded and had lost a lot of metal.....went back with conventional plugs. The driver sides were very clean - no carbonizing at all, but the curb side (#4 and #6) had a bit of carbon/buildup - but not bad.....when the plugs were changed last the #8 cylinder evidenced by far the worst buildup, but it also had a burnt plug wire....#8 looked pretty good this time.

Hard to believe that it's mid September and the temp index is well over a hundred degrees - the good thing about the MoHo being down right now is that it is still too hot to go camping....a very welcome benefit of the metal roof over the parking area is that a couple of well placed fans on the concrete makes it almost bearable when working under the unit.

[elbundi]

bump:
great thread and about where ill have to go after our recent trip with a brake overhaul. you still own your motorhome 87MH?

[Mikethefixit]

Dennis
The way you have done this brake job is the ONLY WAY. Like me WHILE YA GOT IT APART replace everything. Then ya know what ya got.
I have done brake jobs on big trucks that I owned in my day and I know its not all fun an games.
GOOD JOB now You can sit back and enjoy the fruits of your labor.
Roger

[92landyacht]

Bump to keep this up front. Would recommend a sticky thread that contains links to great maintenance write-ups like this. Some times these threads get buried deep into the archives.

[Boom Sounds]

Originally Posted by PeterH-Airstreamer

rear drum brakes on the P-30 are a bitch!
The axle shaft has to be pulled and the drum weighs a ton. I had a leaky oil seal and decided to go all the way, seals, bearings, shoes and wheel cylinders.
Two places here in Austin turned me down on the rear brake job. Did not want to take it to someone I didn't know.
$300.- in parts and lots of my free labor.
I wonder what Mr Goodwrench wants for a job like that.
Best thing they ever did is change to rear disk brakes.

20 years on and I can testify to your analysis. Your contribution to this forum has been immense. I have had an epic fail trying to blled the rear drums after hours and hours of trying. I think it needs a special spanner or possibly swan neck. It looks like 5/16ths, but even that seems a little loose. The nut is rusted on solid. Is it viable to do this without removing the drums etc. If I had the right spanner, i think i could get it in there, whether it would then give me enough torque is another matter. It's a living nightmare because I can't get people out to look at it, can't afford to get it towed to a garage and don't want to attempt the removal of the rear drums myself. Do you think GM had a special tool/spanner to blled these?? Any suggestions welcome

[GWallace]

When I replaced all of my rear brake components on my 1977 Argosy, I found that handling the rear brake drum was a challenge. I used a standard 3 ton floor Jack with blocks of wood. Placing the drum on the cup like pad and stabilized with some blocks of wood, I was able to easily raise the drum up to the correct height and then roll the floor jack inward over the brake shoes and into position fairly easily.
After I got it all together, I then discovered that new wheel cylinder bleeder screw was too tight to get it loose. It all came apart again to take the cylinder out and use a 6 point socket to get it loose. The original cylinder had a 5/16 inch bleeder and the new replacement cylinder had a 1/4 inch bleeder. I just snugged the bleeder closed and re-assembled everything using the floor jack for the drums. With everything installed the bleeder is next to the leaf springs and there was not enough room to install a bleeder hose. I wedged a rag over the bleeder and opened the bleeder with an open end wrench when my son had his foot on the brake (bleeder only open with positive pressure on the system). It was tedious but we finally got the brake system rebuilt and it works great.
Good luck with your endeavor!

[GWallace]

If I were to try this again without removing the drums and bleeder was stuck, the only wrench (spanner) I think that the wrench I would use would be a flare nut wrench or a 6 point box end wrench. The problem is the bleeder screw is so close to the leaf springs that there may not be room for access.

[tjdonahoe]

Originally Posted by PeterH-Airstreamer

rear drum brakes on the P-30 are a bitch!
The axle shaft has to be pulled and the drum weighs a ton. I had a leaky oil seal and decided to go all the way, seals, bearings, shoes and wheel cylinders.
Two places here in Austin turned me down on the rear brake job. Did not want to take it to someone I didn't know.
$300.- in parts and lots of my free labor.
I wonder what Mr Goodwrench wants for a job like that.
Best thing they ever did is change to rear disk brakes.

..them are nothing..been doing brakes on big trucks since 1969...

[PeterH-350LE]

Originally Posted by Boom Sounds

20 years on and I can testify to your analysis. Your contribution to this forum has been immense. I have had an epic fail trying to blled the rear drums after hours and hours of trying. I think it needs a special spanner or possibly swan neck. It looks like 5/16ths, but even that seems a little loose. The nut is rusted on solid. Is it viable to do this without removing the drums etc. If I had the right spanner, i think i could get it in there, whether it would then give me enough torque is another matter. It's a living nightmare because I can't get people out to look at it, can't afford to get it towed to a garage and don't want to attempt the removal of the rear drums myself. Do you think GM had a special tool/spanner to blled these?? Any suggestions welcome

Nick, I thought the 250's have disk rear brakes? If its drum, you may have to bite the bullet, cut the line and pull the back plate with wheel cyl attached.

Too funny, the post you quoted was from May 2003, haha.

[martin300662]

Originally Posted by PeterH-Airstreamer

Nick, I thought the 250's have disk rear brakes? If its drum, you may have to bite the bullet, cut the line and pull the back plate with wheel cyl attached.

Too funny, the post you quoted was from May 2003, haha.

Unfortunately for Nick the 250 has the JB8 brake configuration so the disc/drum combo.

Would it be any easier with the rear wheels off? At least you would not also be fighting with the inward facing dish and tire in the way?

[bkahler]

From my experience with the JB8 brakes on my Argosy there is no easy way to bleed the brakes. I was able to use a tygon tube over the nipple but it wasn't easy. My wheel cylinders and bleeders were new which I'm sure made things a 1000 times easier.

If I remember correctly I used a small box end wrench to break it free. After that I just left the bleeder open and let gravity do the work. No pumping of brakes, etc. I just kept the reservoir topped off.

When I bleed them I opened the bleeder on the left rear brake cylinder and waited until fluid started running out of the bleeder. Keep in mind my brake system was totally new so there was no fluid in the lines and it took a while for the fluid to reach from the MC back to the left rear wheel. Once fluid was flowing from the bleeder I closed it off and then opened the bleeder for the right rear brake. It didn't take long for fluid to start draining from this bleeder as well.

I then switched to the right front and then left front repeating the process. The important thing is to make sure the MC does not run dry. If it does you have to repeat the process.

Brad

[Boom Sounds]

Success at last and I managed to do a full bleed and change the bleed nipples without pulling the drums......prepare yourself for a long painful haul

The problem i had was increasing spongy brakes over a long holiday in France/Italy. Lots of mountain driving in the Alps which is beautiful but very heavy on the brakes. By the time i got back to Calais the check brake light was intermittently on. We ended up getting towed. I had put the issue down to potential collateral damage from a front wheel blow out, but that seems to have not been the case.

I did replace the master cylinder but I suspect the actual cause was the old chestnut of burning out the fluid in the mountains. I've upgraded to DOT4 which has a higher boil point.

Procedure as follows:
Know your VIN and if you can run it through CompNine to get your RPO codes.
VIN:1GBJP37N0M3301377
1991 CHEVROLET VAN P30 ENGINE,7.4L(7.4N),V8(E.F.I.) 7.4N(L19)
V8-454ci 7.4L F/I Vin N #24665 L19 1991 P30 Chevy
JB8 BRAKE SYSTEM,HYDRAULIC POWER DISC,DRUM(GAS & DIESEL ENGINE)(ROTOR=12.5"X1.54",REAR BRAKE SHOE=13"X3.5") HYD PWR DISC/DRUM BRK(JB8)

If you are working on the coach, be sure about your brake set up. If you have the 16" wheels, you probably have the JB8 Front disc/rear drum set up like me. Note that some brake stuff is P32 Motorhome specific rather than a straight P30.

When replacing parts, casting numbers are usually best to ensure the correct application. I find the Dorman and AC Delco sites good for cross referencing parts. The Dorman site lets you specify details like front disc/rear drum.

I took the opportunity to replace all the existing bleed nipples for Dorman speed bleeders.

Dorman 12702 Speed Bleeder M10X1.5 X 32
Dorman 12705 Speed Bleedr M8-1.25 X 27.6

and a new Master Cylinder.
ACDelco 18M230 Professional Brake Master Cylinder Assembly
If you consider replacing your Hydroboost (which rarely fail) do not chuck out the old parts especially the push rod as you need an exact match.

The parts above went straight onto my 1991 250.

The old bleeders were rusted and in bad shape. I used plenty of PB Blaster and let that soak in on a couple of occaisions before attempting the repair. I also used some Normfest Super Crack Ultra Ice Rust Remover. Very good stuff IMHO. The fronts are easily accessible via the front wheel well. I managed to free up the fronts and replace the bleeders with relatively little effort. Take care, don't shear your bleed nipple and if you do, refer to YouTube on how to remove it using pliers or potenially heat.
https://www.amazon.co.uk/Normfest-28.../dp/B00GUS2WN4

Onto the rears... that is a whole different story. They are pretty much inaccessible with little room between the bleeder and the leaf spring. I could just about get a small spanner in there, but had no torque. The ratchets I had wouldn't fit. It seems that GM had a special bleeder wrench which you can buy on ebay for about 80 bucks.

I purchased various cheap spanners off ebay and at the car boot sale. There were some long sockets which could fit over the bleeder nipple.

The one that really sorted out the issue was this swan neck 5/16ths fella - only three bucks! It was the perfect size to fit in there and long enough to get some torque. i could fit another open pole over the end to give more leverage and off they came. Once they were loosened up, I moved onto a 5/16ths straight spanner. I reckon i managed 1/12th revolution at a time, so 12 turns for only one revolution of the bleed nipple.....it takes time but can be done if you can free it up without breaking it. A few hours later, i had replaced both rear bleed nipples. You need to pinch them up tight.

A full bleed from rears to fronts revealed dirty fluid with air bubbles. I've not driven it, but the pedal is firm and no brake light so confident that was the issue and that is has been fixed.

Camping is a thing again, so we hope to get away later this month. Thanks to everyone on the forum for their thoughts and tips.

Hope this helps

Nick