Daves1940Buick56S Posted June 2, 2018 Share Posted June 2, 2018 In the midst of relining the brakes, I wanted to check the master fluid level. So I pulled up some of the carpet and found a round wooden plug in the floor pan. I pried this out, assuming this was the access to the master cylinder. But the master is not directly under the hole but over towards the trans a few inches. I can see the master plug but it appears to be a real b***h to get to. Any ideas here? Would pulling the trans access cover help? Cheers, Dave Link to comment Share on other sites More sharing options...
DonMicheletti Posted June 2, 2018 Share Posted June 2, 2018 Both my '38's are that way and it is a PITA. Makes no sense at all. Very annoying. The 'plug' should be a metal disc with legs to align it with the hole and a fibre disc riveted on top. Link to comment Share on other sites More sharing options...
MCHinson Posted June 3, 2018 Share Posted June 3, 2018 It should be a metal removable cover rather than a wooden plug, but I have to admit that I have no idea how they decided to put that master cylinder so far out of alignment from the access cover. As Don said, the cap should be a metal cap. It is probably not easy to get off even if you could easily get to it. Bob's Automobilia sells a plastic replacement cap that will make getting it off easier the next time. As difficult as it is to get to most people consider it one of those "out of sight out of mind things" until there is a problem. Some type of long funnel will make it easier to refill if needed. I don't think you can pour brake fluid into it easily with the body on the chassis. On my current 1938 project I was lucky to have the body off of the chassis when I took care of the brake system. I think it would be easier to put a wrench on the master cylinder cap from a creeper under the car rather than accessing it through the access cover. Link to comment Share on other sites More sharing options...
Gary W Posted June 3, 2018 Share Posted June 3, 2018 On my '37 Special, the metal access hole lines up perfectly with the master cylinder cap for service. Is there a chance that on the Century chassis the master cylinder is in a different position than the Special, but the body is essentially a Special body and the hole doesn't line up? Link to comment Share on other sites More sharing options...
MCHinson Posted June 3, 2018 Share Posted June 3, 2018 You could be onto something. Both my 1937 Century and my 1938 Century are not lined up well at all. The body shell is basically identical and obviously the access cover was designed for the Special and not the Century. Link to comment Share on other sites More sharing options...
Guest Posted June 3, 2018 Share Posted June 3, 2018 Not original but how about getting a floor pan drain plug (plastic/rubber/etc) and using a hole saw drill through the floor pan. Snap the plug in and the next time it is real easy. https://www.amazon.com/Crown-Automotive-J4000334-Floor-Plug/dp/B009X1TPLW http://dennis-carpenter.com/cowl-and-floor-pan-rubber-plugs/p/352284/ https://www.steelerubber.com/plugs http://www.txdashcovers.com/1nyhopldecep.html Link to comment Share on other sites More sharing options...
DonMicheletti Posted June 3, 2018 Share Posted June 3, 2018 Both my '38 Special and "38 Roadmaster master cylinders have that crazy offset access hole. I use a funnel if I have to fill them. I also remove the caps from under the car. On the Special, there is a spring extension that goes over the whole mess to make it harder yet - I wondered about that being correct. The '37's must be different. Link to comment Share on other sites More sharing options...
Gary W Posted June 3, 2018 Share Posted June 3, 2018 Here's the way the 1937 Special master cylinder lines up with the access hole in the floor: You can see the cap is right under the access hole. Link to comment Share on other sites More sharing options...
Daves1940Buick56S Posted June 3, 2018 Author Share Posted June 3, 2018 I am thinking the hole saw thing is the way to go. If my car was absolutely perfect I wouldn't, but there are already a few "unauthorized" holes and nobody will se this one anyhow. Otherwise I will be beyond frustrated every time I have to access the master. Next week I will get a measurement on the clearance - I think maybe a 4" hole will be good. I can find or fab up a cover. Here is what my current cover looks like. Cheers, Dave Link to comment Share on other sites More sharing options...
Guest Posted June 3, 2018 Share Posted June 3, 2018 I am amazed at the number of things that GM did that appear cobbled together or just plain stupid. The battery access panel in my Pontiac floor board was a metal insert so you could check the battery water without removing the screws and the floor boards. The insert was right under your left heel and if it fell through it was exactly the right size to short out your battery. GM's sole purpose of course was to make a profit for its shareholders and nobody ever expected one of these cars to be in daily service after half a century and more. Link to comment Share on other sites More sharing options...
MCHinson Posted June 3, 2018 Share Posted June 3, 2018 It looks like someone has replaced the original insulating material on your access cover with a piece of wood. Here are photos that show the misalignment with the access hole and the master cylinder on my 1938 Century project. I can't seem to locate which box the access cover for my 1938 Century project is at the moment so I have taken photos of the one on my 1937 Century with the remains of the original insulating material visible on the top. In the first angled photo, you can see the aftermarket plastic cap. I had so much trouble removing the original, I did not want to ever have the possibility of the cap rusting to the master cylinder again. When looking straight down, on either 1937 or 1938 Centurys you can barely see the master cylinder. Link to comment Share on other sites More sharing options...
Bloo Posted June 4, 2018 Share Posted June 4, 2018 Now I have a question for you 1937-38 owners. I understand originally the front floor covering was a rubber mat. How do you access the floor plug over (well, not really over) the master cylinder? Is the floor mat attached? Is it caught or held down any way by the front of the front seat, the kick panel, or the sill? Can you just lift it up (and were you supposed to hold it up like a tent or something while trying to access that master cylinder that isnt quite under the hole)? Another one, what happens where the carpet meets the rubber mat? I saw in GaryW's thread that the rear carpet has two bound strips sewed on that come up along the front seat. How does this meet the rubber mat? Does one lay on top of the other? If so, which way was it? Did they just bind the carpet edge and have the two butt against each other? Link to comment Share on other sites More sharing options...
MCHinson Posted June 4, 2018 Share Posted June 4, 2018 The rubber mat can be folded/rolled up enough to get to the access panel. It would probably be better to totally remove the rubber floor mat for access. It lifts up easily. The rear carpet does not extend all the way under the seat anywhere near the rubber mat. Under the front seat you see the metal floor. There are narrow sections of carpet that extend between the rear carpet and the rubber mat on the outsides of the seat bottom. Off the top of my head without looking at the car, I think they simply butt up against the rubber floor mat, or possibly the floor mat extends slightly over them. 2 Link to comment Share on other sites More sharing options...
Daves1940Buick56S Posted June 4, 2018 Author Share Posted June 4, 2018 I thought I posted this but must have forgotten to hit Submit. Anyhow, after looking at Matt's images it is apparent the MC filler opening is right under the strip of metal between the filler opening and the transmission floor cover opening. The easiest thing would be to take my Sawzall and cut out that strip, otherwise I will be swearing up a blue streak every time I have to access the master cylinder. Cheers, Dave Link to comment Share on other sites More sharing options...
MCHinson Posted June 4, 2018 Share Posted June 4, 2018 It is a bit obnoxious, but how often do you expect to be trying to check the fluid level or adding any fluid? For an average antique car without any leaks, you really are not going to be bothering with that very often. I am embarassed to admit how long I have gone without bothering to check the brake fluid. The brakes have basically never given me any problem in 4 years of ownership of the 1937 Century. 1 Link to comment Share on other sites More sharing options...
Daves1940Buick56S Posted June 4, 2018 Author Share Posted June 4, 2018 Well I hope not, but I just got this car and am "learning" it now. I am already replacing the front brakes and assume the backs are the same. No leaking around the front cylinders but the backs are unknown. I also have to take a close look at the steel lines. I could be in for a couple of bleed sessions over the next 2 years and I know it would drive me nuts. Cheers, Dave Link to comment Share on other sites More sharing options...
dibarlaw Posted June 4, 2018 Share Posted June 4, 2018 (edited) Agree to all said above. One of our Mason-Dixon club has a 1938 Century Sedan. At our car show several years ago he inquires as to how to check the brake fluid. I showed him how to access the floor cover on my 37 Special. Easy.. no problem. Then we walked over to his 38 and tried to pull up the carpet ...... it was glued down to the floor!!. So no access. I know he had the car over 5 years and never checked the fluid. On our 1936-38 tour down around Nashville several years ago. One member with a pristine 38-41 had his brakes lock up in the middle of an intersection in Bell Buckle TN. Several members were all over the car to turn brake adjusters loose so we could push it over to a parking space. Luckily I had a wrench in my tool kit I carried with my 37 that could break the cap loose off the master cylinder. What a PIA! What was inside was a sticky gooey mess more like creosote than the syrup that one usually sees in very old brake fluid. Ralph, our technical advisor used a variety of the tools /rags available to get most of this mess out of the unit. Joe Suarez in the back round commemorating the event. We used all of the spare can of brake fluid I had. I went to a local convenience store to buy more so we could try and flush some useable fluid to the wheels for bleeding. It took us over an hour but we had him back on the road. The green 38-41 had boiled over. When we got the radiator cap off any sludge that was in the block was loosened and packed the radiator solid. Cause and effect.... CAUSE-Dragging Brakes....EFFECT-severe overheating. Edited June 4, 2018 by dibarlaw Added content (see edit history) Link to comment Share on other sites More sharing options...
DonMicheletti Posted June 4, 2018 Share Posted June 4, 2018 Mat is right. While checking the MC or adding fluid is a PITA. You dont have to get at it very often. I converted both Buicks to silicone fluid and the only time I had to access the MC is when I replaced the clutch, maybe 15 years ago. While I check the fluid level occasionally (actually very rarelt). I have never had to add fluid. Link to comment Share on other sites More sharing options...
jeff Posted June 4, 2018 Share Posted June 4, 2018 Just my two cents... You should be checking the master cylinder at least twice each driving season! A single circuit brake system with no fluid level sensor as found on modern cars - leads to a very, very bad failure mode. My '38 Special with a re-sleeved, rebuilt master cylinder still weeps just a bit out the back of the master cylinder. Happy to hear that yours do not, but a bit more wear or hardening of the seals and I would guess they may start to weep. Same goes for your wheel cylinders. I would recommend checking frequently. As far as misalignment, my Special is also a pain - maybe not quite as bad as the Century pictured in this thread. I have gotten used to using a cut down wrench, and a very careful pour. Maybe in your case you could rig a syringe with a tube to introduce some fluid in spite of the offset. This approach works from underneath as well. A clean finger can act as a dip stick. In some ways our old cars are woefully inadequate - so we need to keep them as safe as possible! Just my opinion. Take it for whatever its worth. Jeff 1 Link to comment Share on other sites More sharing options...
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