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1968 brake booster issue

Started by Trace, July 13, 2020, 05:08:00 PM

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Trace

   I am new to this forum, but have been helped immensely by the info found here. I am in the process of partially restoring my deceased father's 68 Deville convertible. While taking it out to test the revived cruise control, the brake pedal went stiff and the brakes were almost non-functioning.  I nursed her home and went out two days later, started her up and the brakes were fine. I've already went through the vacuum system for leaks while restoring the power servo so what I'm left with is a malfunctioning booster. My dad was an auto mechanic (private shop) so I spent many a day helping him at the 'station' in the 70's. I don't recall ever seeing dad pull off a booster. I have the manual that tells how to do it (the manual was not that much help when I had to pull the dash) but was wondering if it was worth breaking it down and rebuilding it. Has anyone done this? Could it be it's just age related corrosion that needs to be cleaned up? Are replacement /rebuild kits even available? Based on pictures in this forum, it is a Bendix. Thanks for any help you can give.
Blessings, Tracy

Reviving my Dad's 1968 Deville Convertible
1964 Impala SS Convertible w/409 -SOLD
1964 Thunderbird Convertible - SOLD
1969 GTO Convertible - SOLD
1958 Impala - SOLD
Luke 12:31,32
Heb.10:36

cadillacmike68

It's a booster and / or master issue, and both should be replaced, especially if they are the originals. A similar thing happened to me a couple years ago with my 1968 DVC. The problem came and went and then came to stay.
Regards,
"Cadillac" Mike

chrisntam

I have a pretty hard brake pedal on my '70, replaced the booster, MC, WCs, calipers and some metal lines & rubber hoses, no difference.  It's almost as though the booster wasn't getting enough vacuum.  I removed the hose to the booster, idled the car and tried to stop it, I really couldn't stop it.  Still chasing the source of the hard pedal.

Were you able to actually stop the car without use of the booster?  You might call "Booster Dewey", he advertises in Hemmings, he rebuilds them.  I haven't used him, but he's got a pretty good rep in the industry. Give him a call to see if you have a booster issue, he may be able to diagnose your situation.

http://boosterdeweyexchange.com/

Be sure to circle back around and let us know the outcome.  And welcome to the site.  Sorry about your dad, I lost mine almost a year ago.   :(
1970 Deville Convertible 
Dallas, Texas

35-709

Check with Booster Dewey first ( 503-238-8882).  A few days ago he was running several weeks behind on his overhauls.  I ended up sending the booster from my '68 Bonneville to Power Brake Exchange in Santa Fe Springs (562-806-6661), they assured me 3 day turn around.  We'll see, UPS just delivered my booster to them today.
One problem I had on a '72 Cadillac (and I've told this story before) --- the brakes worked fine until it got hot under the hood, then the pedal would get hard and stopping the car was difficult.  Long story short, the vacuum hose from the base of the carb to the booster was failing internally, as it got hot it would get soft and collapse from the vacuum.  Replaced the hose and the brakes returned to working normally.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Cape Cod Fleetwood

You can also reach out to John Abend on Facebook on his page "The 1965-1970 Cadillac Collective". He's really good at troubleshooting things like this and probably has a box of boosters in his shop somewhere if you need one.
There are 2 kinds of cars in the world, Cadillac and everything else....

The Present -1970 Fleetwood Brougham

The Past -
1996 Deville Concours
1987 Sedan De Ville "Commonwealth Edition"
1981 Coupe De Ville (8-6-4)
1976 Sedan De Ville
1975 Sedan De Ville

The Daily Driver and work slave -
2008 GMC Acadia SLT *options/all

Trace

Many thanks for the info. I have just replaced the vacuum hose to the booster (it appeared to be original) and will take it out for 20 miles or so one day soon. I was taught to do the easy stuff first.
   If the booster needs to be replaced/rebuilt, I take it that it is not anyone's desire to rebuild one yourself. I was hoping it was easier than the manual made it look ..... maybe it's not. Along those lines, both NAPA and O'Reilly's state that the Bendix boosters were usually painted black and the Delco were an anodized gold. Is this correct info? I am now questioning which manufacturer's booster I have .....
Blessings, Tracy

Reviving my Dad's 1968 Deville Convertible
1964 Impala SS Convertible w/409 -SOLD
1964 Thunderbird Convertible - SOLD
1969 GTO Convertible - SOLD
1958 Impala - SOLD
Luke 12:31,32
Heb.10:36

35-709

Yes, the Bendix boosters are usually painted black.  The word "Bendix" should be stamped in the bottom of the booster, may be very difficult to find and read on an original booster that has been in service this long,  read it with a mirror.  The numbers 5115 will also be there, one or the other is confirmation.  NAPA, O'Reilly's, Advance Auto Parts, Auto Zone, etc. may say they have rebuilts available, but they don't.  You will have to wait quite a while to get one.  Same for rebuild kits.  Last I checked, Rockauto offers a rebuild service, but you have send them your old one and wait until some time in September for you to get yours back, rebuilt.

I ordered a rebuilt booster from eParts recently (June), they replied with a delivery date of about 1 week, when the delivery date came and went, I contacted them, basically their reply was, "oh, they are not in stock and we don't know when they will be."  I asked how they could possibly give me a delivery date (via FedEx they said) when they didn't even have one to send, the response was, "sorry, sir, I don't know."
     
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Trace

   It seems that the hose was not the problem. So we move to plan B ....
   The best price on a rebuild that I've found was indeed the RockAuto/Cardone (#5481117; $77+). RockAuto customer service stated the turnaround to be 20 days. Harmon Brakes has a complete rebuild kit ($125+) as well as a rebuild service ($225); turnaround two weeks. Harmon supplies the kits to Booster Dewey/Power Brake Booster Exchange. Their rebuild price is $175+; turnaround 4-5 weeks.
   I am leaning toward the Harmon kit; I really enjoy tearing into things to see how they work. I do know the kit will be quality if the Booster Exchange uses them. I called a local classic car repair shop (VA.) and they told me all of their boosters go out to the Booster Exchange in Oregon for rebuilds.
   I may take pictures of this endeavor. It can't be any worse than pulling the dash and bezel out.
Blessings, Tracy

Reviving my Dad's 1968 Deville Convertible
1964 Impala SS Convertible w/409 -SOLD
1964 Thunderbird Convertible - SOLD
1969 GTO Convertible - SOLD
1958 Impala - SOLD
Luke 12:31,32
Heb.10:36

35-709

According to UPS tracking, my rebuilt booster from Power Brake Exchange in Santa Fe Springs, CA should be delivered to me here in FL tomorrow (Wed.).  Not counting shipping out and back that is a 3 day turnaround for $165 which includes shipping back to me.  So far so good and I am most pleased, the proof, of course, will be when I install it and see how it works. 
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

cadillacmike68

Try O' Reilly's I got a master and booster from there and thef fit perfectly. You can change to the Delco Moraine, if you change Both the master and booster.
Regards,
"Cadillac" Mike

Trace

  I called the 'big 4' free standing auto parts stores and all told me that the booster was out of stock and they had no idea when they would be available again (one said, "...,if ever."). If you picked up one recently, that's a blessing!
  To update my first post, I do have a Delco setup. I thought it was a Bendix based on a photo posted in the forum out of a '67 Eldorado manual. It was a gold-ish booster and the MC with the caption; 'brake booster and MC - Bendix'. It matched mine perfectly. It seems the photo was mislabeled. I've since found out that the Bendix setup was usually painted black.
   
Blessings, Tracy

Reviving my Dad's 1968 Deville Convertible
1964 Impala SS Convertible w/409 -SOLD
1964 Thunderbird Convertible - SOLD
1969 GTO Convertible - SOLD
1958 Impala - SOLD
Luke 12:31,32
Heb.10:36

35-709

 ;D  Yes, read the first sentence in my Reply #6.   ;D
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

cadillacmike68

I got my booster and master a year or so ago, so yes, they might be not readily available at present. They are a pain to rebuild.
Regards,
"Cadillac" Mike

Trace

Well, I've finally decided to 'dive into the deep end' (...and I can't swim .... really). I purchased one of the Harmon brake booster rebuild kits several weeks ago and started the rebuild this week.
  Naturally, the first thing to do was to pull the booster. The manual suggests that the brake lines be disconnected and the master cylinder be drained and left attached to the booster when removed. That was not my first choice, ... since I did not want to try to bleed the brake lines after the reassembly by myself. Working with my dad, bleeding the brakes was a two person job. So I unbolted the master cylinder from the booster and gingerly pulled her out and away, ...bring mindful not to crimp the lines. I followed the manual for the rest.
   I added note that is not mentioned in the manual that makes the under-dash work less aggravating. The lower right hand booster mounting bolt is behind the neutral switch. Life and nut removing is easier if you pull the switch and drape it toward the center of the car. It'll hang there fine. Once the final nut was removed (following the manual's steps), the booster was able to be pulled from the firewall and maneuvered around the master cylinder.
   It appears that sometime in the past, the master cylinder leaked down the front of the booster. It was fairly corroded. I'll try to post pictures.
   Next post: Separating the shells .....
Blessings, Tracy

Reviving my Dad's 1968 Deville Convertible
1964 Impala SS Convertible w/409 -SOLD
1964 Thunderbird Convertible - SOLD
1969 GTO Convertible - SOLD
1958 Impala - SOLD
Luke 12:31,32
Heb.10:36

2danreed

I rebuilt the booster on my '64. It was a Bendix. The booster came out without draining the master cylinder, just carefully moved it out far enough to get the booster out. Rebuilding was easy and straight forward. The diaphragm went bad on the original causing the hard pedal. The hardest part of the job was getting the two halves of the housing apart :)
Dan Reed

Steve W

Welcome Tracey,
I replaced my master cylinder and the front brake lines a few years ago, but haven’t had any issues with the booster, so I’m no help! Although I wouldn’t rebuild it, I’d just replace it if possible. But that’s just me, I don’t think I’d be patient enough to rebuild it.

Sorry to hear about your Dad, but I’m glad you’re keeping and fixing up his/your car! Good luck with everything. And keep us posted on your progress!
Steve Waddington
1968 Coupe deVille
North Hollywood, CA
CLC Member # 32866

Trace

#16
   A few observations during the separating of the shells:

  1) The rust/corrosion on the lower shells and seams makes easily unlocking the halves difficult (pic 1&2). A simple 'twisting off' was not going to happen, so I (a) PB Blaster-ed the rusted seal (reminder; all traces of petrolium /oil based solvents must be removed with alcohol); (b) slightly pried up the tabs in that rusted area to allow some Blaster under the seam; (c) wedged a large screwdriver between a tab on the one half and the locking channel on the other, .... and gently pry the tab away from the channel. This probably won't free it up enough, but it was encouraging to see it move; (d) used a smaller screwdriver to bend back the rusted locking channels to eliminate as much pressure and friction as possible. This last step would be all that was needed to unbind the halves.

  2) Instead of that expensive tool the manual says to obtain, a crowbar across two of the four studs along with two hands pushing down and twisting the unit, freed her up. I used my hip to move the crowbar.

  3) Once separated, you can see the original luster of the booster's outside by observing the inside of the front shell (pic 3). There is a company called Brakebooster.com that will rebuild these Delco booster's along with replating/ anodizing the shells. Their work is beautiful and their website states they work on boosters from all GM nameplates ... except Cadillac is not listed. I am going to attempt a pseudo-anodized finish with primer and paint ... since my shells are seriously pitted.
(Having trouble posting pics)

Next: the Power Piston dis-Assembly


Blessings, Tracy

Reviving my Dad's 1968 Deville Convertible
1964 Impala SS Convertible w/409 -SOLD
1964 Thunderbird Convertible - SOLD
1969 GTO Convertible - SOLD
1958 Impala - SOLD
Luke 12:31,32
Heb.10:36

Big Fins

Hmmmm...Your pictures never showed up.
Current:
1976 Eldorado Convertible in Crystal Blue FireMist with white interior and top. (Misty Blue)
1969 Fleetwood Brougham in Chalice Gold FireMist with matching interior and top. (The Old Man) SOLD!

Past and much missed:
1977 Brougham de Elegance
1976 Eldorado Convertible
1972 Fleetwood Brougham
1971 Sedan de Ville
1970 de Ville Convertible
1969 Sedan de Ville
1959 Sedan deVille

DeVille68

Thanks for the updates, I will tackle this rebuild this winter. I already bought a rebuild kit.

Best regards,
Nicoals
1968 Cadillac DeVille Convertible (silver pine green)

Trace

The Power Piston breakdown is almost 100% 'by-the-book'. Just a few observations:

  1) As per pic 1, the Support Plate on my PPA (Power Piston Assembly) has to be rubbed down. The corrosion is very mild, but the desire is to have it all smoothed out. Honestly, the worst of it is on the edges of the support plate where the lip is. Condensation (from infrequent driving) must have collected in the lip and when the car was started .... and the vacuum ensued ... it pulled the water up out of the lip toward the check valve. And because the car was seldom driven any distances, the plate must have never gotten a chance to dry. I'd love to see the plate of a daily driver to see if my theory holds.

  2) A vice is nice, ...but I don't have space to set one up (I have tools and products for every 'man-hobby' known to senseless men .... I have no room to work in my workshop). So I grabbed an old metal patio table and stuck the brake pedal push rod down through the umbrella hole and grabbed the end of the rod with vice grips (hey, .... it worked). Steps 12-17 (page 5-23, manual) were done here. I had to grab the vice grips for step 18. Pics 2-5 show the disassembled parts.

  3) The manual now calls for another 'special tool' (Power Piston Insert Wrench) that is designed to hold the Power Piston Insert so one can twist the Support Plate off the insert. Within the instructions of the Harmon rebuild kit I purchased, there is info on a company that still makes this tool. But you need a table vice .... which I don't have ... to mount the special tool. So I just twisted it off by hand. It was rather easy. You place one edge of the support plate/ diaphram between your legs/knees; ... grab the power piston insert using both hands on both sides of the plate; ... and just turn it to unlock it from the plate. I wish the outer shells were that easy. Pic 6 is everything separated and accounted for.

  4) The instructions for the Harmon kit state that the 'Air Control Valve' should not be removed .... though the manual says to pull it (step 18). If you go with Harmon, I think that statement may be for other boosters because the kit offers a new 'O' ring for the control valve which can only be replaced by removing the valve from the insert. This is a list a the parts in the kit:


Kit Includes:
1-62-294 Diaphragm
1-62-286 Fr Housing Seal
2-62-287 Push Rod O-Rings
1-62-157 Check & Grommet Kit
1-62-288 Reaction Bumper
1-62-289 Lock Ring
1-62-290 Control Valve O-Ring Lrg
1-62-291 Poppet Valve
1-62-292 Muffler
1-62-296 Air Valve Rod Pin
1-62-295 Rear Housing Seal
1-62-161 Push Rod Boot


Next: Cleaning and reassembly of the Power Piston Assembly

Blessings, Tracy

Reviving my Dad's 1968 Deville Convertible
1964 Impala SS Convertible w/409 -SOLD
1964 Thunderbird Convertible - SOLD
1969 GTO Convertible - SOLD
1958 Impala - SOLD
Luke 12:31,32
Heb.10:36