The GEN light on my 1965 Buick Skylark stays on? What could this be? my voltage maybe or will it go away? I wanted to get some advice on my drum brakes and my current issue i with my brake peddle. My brake pedal sinks to the floor... Could this mean my brake booster has gone out? I managed to take off my rear drivers side drum and I'm thinking about rebuilding the current drums so that I can save a little cash. What pros and cons would I have with drum brakes vice doing the converstion? Thanks for your help.
Sinking brake pedal = bad master cylinder. Properly functioning drum brakes should stop the car just fine.
Others more knowledge able on the GEN light will chime in but I'd suggest that you pull the alternator and have it checked, most national auto parts stores will do it for free. Testing the voltage regulator is more involved but if you're good with a multimeter and follow the checks you could check it. I agree with master cylinder as the brake iissue.
rockauto has a Master Cylinder Repair Kit for 15 bucks. Has anyone use it? Or should i just buy a new one?
Buy a new one, don't cheap out on a kit. Make sure you buy a master cylinder for drum drum brakes. Meaning drum front and drum rear. Then have some bench bleed it before you install it, to get all the air out of the new master cylinder. Flush out the brake system while you are in the closed brake system. As soon as you open the brake lines, you just added air and moisture. Brake fluid is cheap at a parts shop. While you are on Rockauto site, but a new regulator too. The new ones are electronic where the old regulators are more mechanical.
Before spending any money take the time to pull all the drums and check the wheels cylinders. Pedal leak down can be a leaky cylinder too but you should have a loss of fluid. No better time to check the brake hoses too, you may even have a hose swelling causing pedal drop. Reconditioning your brakes? Up to you, personally i prefer to leave that to the pro's and have a warranty with it. Brakes IMO are not something to skimp on. No better time to inspect the drums, shoes and hardware. If you have pedal leak down with no fluid loss than like the others mentioned it is most likely the master cylinder.
I have to agree with woodchuck2. You need to properly inspect and diagnose each wheel to make sure that there are no leaks before you assume that it is the master cylinder. A leaking wheel cylinder (brake cylinder) or brake line will also give you a sinking brake pedal.
A leaky wheel cylinder will attract dirt. So if you see one that has an accumulation of dirt by the rubber cups, its leaking. Sometimes, you can peel back the dust boots on the wheel cylinders and look for moisture. Moisture= bad. And if you do any brake work, PLEASE use the right tool to remove and install the drum springs. DO NOT use a screwdriver or other similar tools. And wear safety glasses!
To address the generator light issue - put a volt meter on the battery with the engine off. A good battery will read somewhere between 12 and 13 volts. Now start the engine and check the volt meter. If the charging system is working you should see more than the voltage that you had when the engine was not running. A good alternator puts out about 14 volts. If you increase the engine speed sometimes the voltage level will rise a little. Also check the condition of the battery cables - corrosion and looseness can cause problems too.
OK... First the story and then the question: had a 1974 Olds Twister (Toronado) and when it was wet ouside I only had rear brakes, evident by locking and sliding, but no sinking pedal. Mechanic guy tells me it a proportioning valve gone bad. I changed that out myself and no go. It was in fact the bad master cylinder scene. So now its time to Give me a BRAKE! Cloned out 72 GS 350 into a 455 GSX. Car came with 4 drums and PO switched the front to regular old GM discs... the whole schlameel. On top he left the original master cylinder, and diaphragm in place, with NO proportioning valve. Hot, cold, hard stops or easy, wet or dry, the car stops fine. The MC is leaking now and I want to change that and a new booster for cosmetics. Ill get a Cardone locally, but which one?? The 72 GS listed drums yet the base skylark was disc. (My 1970 455/4speed had the big aluminum drums and my 1971 455/400 had discs, for reference). I just wanna get the right master that works, and not get into installing a prop valve. Please don't guess or surmise, but tell me whats what here. The PO ran most new lines/hoses below so the juice is recent and no rear wheel leaks. And of course the age old question... are the reservoirs reversed? Large to the rear brakes and smaller rear cup to the discs?? Just tell me what MC please!!! Thanks for the guidance! Bill in TR
WILL DO! But, is the one on the car disc or drum now? If its drum and I get a disc MC will I need to install the prop. valve? Just dont wanna make a mistake $$$ Rock Auto lists the drum and drum MC as AC Delco 18M13 and the AC Delco disc and drum MC as 18M878 Seems more skylarks had the discs and the GSs had the drums. Mine was a GS 350 with drums originally converted to discs. Thanks Bill in TR
The 1972 cars used a combination valve. The combination valve was mounted further down the frame in all disc brake cars. It consists of a proportioning valve, a hold off valve and the sender for the warning light. With no proportioning valve, the rears can lock up with heavy brake application. The hold off valve holds the front disc brakes off a bit until the rear brakes apply. The all drum master cylinders MAY have residual valves, like check valves that keep some pressure in the lines for drum brakes. That might cause the disc brakes to drag. The master cylinders for drum and disc brakes differ in the piston diameters. They are 1" and 1 1/8" respectively. I have no idea which master cylinder is on your car. You have the car:grin: Look for some casting numbers to try and identify it.
"Clean it and ID it..." That's the best idea yet!!! I haven't gotten around to that just yet, but that makes sense. There was some discussion on that a while back about the Part # being on the very bottom and kinda hard to read, no?? Ive heard of the hold off valve from years gone by but I thought they quit using those in about the 68-69 model years. Hmmm. There is a brake warning wire hanging out of the harness by the junction block, but no place on the MC to plug it in to. The only other artifact unearthed, is what I believe is the brake line junction block, way down low by the column lock/ trans shifter cross shaft. Please bear with me as I am just trying to be methodical and not just tear **** up. Heres a pic from the valley of the kings LOL... Bad pics but I am not ambidexstraneous by any means. This does , after some studying, appear to be a prop valve with the signal post between the lines though. Am I getting warm?? ws
From what I have seen in other cars, that looks like a disc brake MC. The drum brake MC's I've seen have equal size reservoirs. Disc have larger front reservoirs. Don't take my word for gospel, but that is my deduction.
The hold off valve was separate and mounted up near the MC from 68-70. In 1971 and up, they moved that function together with the proportioning valve and warning lamp to the combination valve. If that is the old drum brake junction block, that is where the wire attaches, not near the MC. Bill, you know what I tell everyone here, right? Where is your 1972 Buick Chassis manual?:grin:
Oh Merciless Ming I beg forgiveness! (interject humor here!)... I do have a service manual and a chassis manual, but sometimes they seem like theres too much info buried within! So now I hafta back up... I started out as a little kid working on Model T Fords with my dad. By the time I started driving, we ALL knew those things by heart. Overhaul an engine by just being a mechanic. That's the way it was done in days of yore. I started driving in 1971 and bought my brothers factory ordered 1970 455/4 speed car from him (it was 2 years old for $2500 !) with 25,000 miles on it and even used the protecto-plate for warranty work! Restoration back then was not even a forethought. Now, 40 years later, these cars are just as much pieced together as the Model T's were back then...The only difference being that the higher tech cars (by 70's standards) seem more gentrified. I just figure that guys that have had their hands in or on them in the last 20 years know all this stuff from looking at it; not so, and my apologies from being such misogynist. As a BIG DUMMY, my first question is about the IDing model numbers in the books... theres 4200, 4300 and 4400 models. Im guessing those are skylarks, big cars, and Rivs; close on that? Looks like the DaVinci code sometimes when yer a$$hole deep in something and need to look it up, BUT, I did take your advise (and a wire brush) and got a number off the bottom of the MC... Looks like a 1-1/8" piston made in '72?? Also up closer examination, the Prop valve appears mounted on the frame. I was confused as the PO supplied a new one with the car and said he didn't install one with the conversion job. He was NOT the sharpest knife in the drawer and I honestly believe he farmed out a LOT of the work... like a professional GM 1/4 panel and trunk job, yet theres wires twisted together with tape on the charging system. Lotsa Hmmms here, so please bear with me... Bill in TR
Your pics all show disk brake hardware. Your brake lines look like OEM or at the very least very rusty repops. It's very unlikely that the lines are swapped as they are different size tubes and fittings at the MC and prop valve. From the looks of things be prepared when you start this swap that your old rusty lines may not want to let go of that master cylinder. If not you might get lucky by applying some heat wrench lovin but you may start a cascade of parts and line replacements so don't be surprised.
