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View Full Version : Webb/Whacheon Lathe Brake Problem



jbacc
04-22-2016, 09:40 PM
Good Evening,

I purchased a well used Webb/Whachon WL435 17x40 lathe. I am slowly going through it and I am really pleased with my progress and the overall design and quality of the lathe.

I needed a new master cylinder for the brake, with the help of others including many from this site, I was able to cross reference and buy a replacement at an auto parts store.

I installed the new cylinder and bled the system but I am having an issue where the brake does not want to release. It seems the caliper is holding pressure and not releasing the pads. No matter how many times I bleed the system, I cannot get it to work properly. If I induce air into the system, I can pump the brake bar it will build pressure and again the spindle will stay locked up or be extremely difficult to turn.

I have to open the bleeder to release the pressure. Even when it seems to be turning free, after the lathe runs a while the disc gets so hot it begins to smoke. Fluid flows freely hen I open the bleeder and pump the brake bar.

Any insight and/or advice outdoor be much appreciated.

Thanks,

Joe

Hopefuldave
04-23-2016, 04:12 AM
Hi Joe,
I've had this on cars and bikes more than a few times, going to assume (dangerous) that the new M/Cyl is good, it could be a hydraulic hose at the end of its life (the lining can swell, collapse and form a one-way valve all by itself), the caliper piston/s could be sticking due to corrosion or old hardened seals - if the disc is getting hot with the bleed nipple open it suggests the problem's most likely a sticking caliper piston.

If the piston's corroded, check the dimensions against motorcycle calipers, there are only so many (probably metric) sizes, or you *may* be able to clean it up and polish it enough to get a fluid-tight seal (perhaps filling any pits with epoxy and flatting), definitely use new seals and fresh fluid!

Dave H. (the other one)

EDIT: Forgot to say, with the bleed nipple open (better, removed) the piston should move with thumb pressure, with a cylinder full of air and closed bleed it should "bounce" on the air spring, slowly but surely returning to rest position

Black_Moons
04-23-2016, 07:11 AM
+1 for hydraulic brake hose for some reason is so tiny ID they swell with age and pinch off. (Heaven forbid your brake hose be 100% brake fluid compatible, that would just not do..) Just find the rubber hose in the system that will be the one. High pressure of the master cylinder can get oil past the pinch, but the low pressure return of the spring on the slave cylinder can't force it back.

If opening the bleeder nipple fixes the issue, you know the slave cylinder works fine and its a issue with the hose. MAYBE an issue with the master cylinder but im going to say 99% hose.

If removing the connection from the master cylinder does not fix it like opening the bleeder valve after its pressurized up, 100% hose.

jbacc
04-23-2016, 01:47 PM
Hi Dave and Blue_Moons, thanks so much for taking the time to respond to my request for assistance, I also posted a request on PM. Most of the problem was a residual check valve that apparently some master cylinders which have been designed for drum brakes have. I removed it and most of my problems went away. I did remove the caliper to clean it up and while there was no corrosion the dust seals were swollen from oil and one had a bunch of tears and could not be reinstalled. The brake is working quite well but now I am on the hunt for a caliper rebuild kit or a rebuilt caliper. I am trying to figure out the cross reference part number so that I might get it at an auto parts store. If anyone has a part or cross reference number for the caliper on my Webb/Whacheon WL435 17x40 lathe I'd appreciate it.

Thanks again for your help, I truly appreciate it.

Joe

pinstripe
04-23-2016, 04:56 PM
I don't know the caliper part number, but according to a post over at PM, the pads are FMSI D51
http://www.yoyopart.com/oem/507665/fmsi-d51.html#application

The linked page has a list of cars that use those pads.

jbacc
04-23-2016, 05:00 PM
I don't know the caliper part number, but according to a post over at PM, the pads are FMSI D51
http://www.yoyopart.com/oem/507665/fmsi-d51.html#application

The linked page has a list of cars that use those pads.

Yes, I have the information for the pads, it seems no one has posted any information about the caliper. I am hoping someone with the information will post it. Thanks.

Joe

pinstripe
04-23-2016, 05:12 PM
If you can't find a part number, you could try the parts desk of a Korean car dealership. Might get lucky. I think I read somewhere that some of the brake components are off a Hyundai.

jbacc
04-23-2016, 05:37 PM
If you can't find a part number, you could try the parts desk of a Korean car dealership. Might get lucky. I think I read somewhere that some of the brake components are off a Hyundai.

Thanks for the idea... Joe

Black_Moons
04-23-2016, 05:47 PM
Hi Dave and Blue_Moons, thanks so much for taking the time to respond to my request for assistance, I also posted a request on PM. Most of the problem was a residual check valve that apparently some master cylinders which have been designed for drum brakes have. I removed it and most of my problems went away. I did remove the caliper to clean it up and while there was no corrosion the dust seals were swollen from oil and one had a bunch of tears and could not be reinstalled. The brake is working quite well but now I am on the hunt for a caliper rebuild kit or a rebuilt caliper. I am trying to figure out the cross reference part number so that I might get it at an auto parts store. If anyone has a part or cross reference number for the caliper on my Webb/Whacheon WL435 17x40 lathe I'd appreciate it.

Thanks again for your help, I truly appreciate it.

Joe

Wow weird, a check valve. Wonder why on earth it would have that? I don't think parking brakes can be hydraulic can they?

Maybe it was only designed to keep the line lightly pressurized so the drum brakes stayed 'adjusted' to the drums?

jbacc
04-23-2016, 06:25 PM
Ok, admittedly, I'm not the sharpest knife in the draw but I figured if the brake pads for a 1967-1980 Triumph Spitfire were a perfect match for my lathe, I might as well see if the caliper would be too. I did a search and have to admit, the picture of the caliper looks like the caliper in the lathe.

BECK/ARNLEY 077-0216S is the part number I came up with. If anyone with a similar lathe cares to look at it at and offer an opinion I sure would appreciate it.

http://www.autopartswarehouse.com/sk...077-0216S.html

The only concern I have is I do not see the port where the brake line would attach. The caliper on the lathe attaches right in the center where the depression is on the one in the photo.

jbacc
04-23-2016, 06:25 PM
Wow weird, a check valve. Wonder why on earth it would have that? I don't think parking brakes can be hydraulic can they?

Maybe it was only designed to keep the line lightly pressurized so the drum brakes stayed 'adjusted' to the drums?

I think that is the exact reason...

pinstripe
04-23-2016, 08:51 PM
BECK/ARNLEY 077-0216S is the part number I came up with. If anyone with a similar lathe cares to look at it at and offer an opinion I sure would appreciate it.

The only concern I have is I do not see the port where the brake line would attach. The caliper on the lathe attaches right in the center where the depression is on the one in the photo.

The casting is similar, but it's not the same as mine. There are some numbers in the casting. The bottom appears to be the year of manufacture. I cannot read the top one. Does yours have any numbers in the casting?

Is this what yours looks like?

http://i1168.photobucket.com/albums/r491/pinstripe2/HSM/4_zpspz4j7obc.jpg

jbacc
04-24-2016, 12:44 AM
The casting is similar, but it's not the same as mine. There are some numbers in the casting. The bottom appears to be the year of manufacture. I cannot read the top one. Does yours have any numbers in the casting?

Is this what yours looks like?

http://i1168.photobucket.com/albums/r491/pinstripe2/HSM/4_zpspz4j7obc.jpg

I really appreciate you taking the time to post a photo and respond. My caliper looks more like the one in the link than the photo of yours. Yours has socket head cap screws where mine has hex head screws just like the one in the link. However, where the line attaches t the caliper is the same as yours, the linked caliper does not show a fitting in that spot. I also noise another fitting with a line attached at the bottom f your caliper, mine does not have that.

pinstripe
04-24-2016, 11:50 AM
I also noise another fitting with a line attached at the bottom f your caliper, mine does not have that.

The line at the bottom wraps around to the back of the caliper to drive the other piston. Does yours have one or two pistons?

If the casting in the link looks the same as yours, then you might be OK with the rebuild kit even though there are minor differences. As you noted, there is a little indentation in the caliper where your line runs in. The manufacturer probably designed the casting for different applications, and they drill/tap the holes required by the customer.

jbacc
04-24-2016, 02:39 PM
The line at the bottom wraps around to the back of the caliper to drive the other piston. Does yours have one or two pistons?

If the casting in the link looks the same as yours, then you might be OK with the rebuild kit even though there are minor differences. As you noted, there is a little indentation in the caliper where your line runs in. The manufacturer probably designed the casting for different applications, and they drill/tap the holes required by the customer.

Mine has two pistons but the fluid passes through one casting to the other and there is a small seal to prevent them from leaking. The brake works great now but the dust seal is missing so I will take it apart when the rebuild kit comes and hopefully put this to rest. I really appreciate your help.

Joe