Brake Cylinder Piston Lube

Rebuilding the cylinders and want to know what sort of lube to use on the rubber pistons.
Thanks

 

Brake fluid.

 

X2 using anything else will contaminate the system, Ron

 

Do any honing, then use alcohol to clean the cylinders, then brake fluid to lubricate the pistons. Ron is right; completely clean, and nothing but brake fluid in the cylinders.

New cylinders are not expensive for most applications.

 

This. I used to hone them and so on, not any more.

 

thanks guys...i've also read about red rubber grease that is made from vegetable oil and is compatible with brake fluid. I want a light film for the assembly...

 

Only brake fluid. Thats it.

 

x2

 

brake fluid has plenty of lubricity by itself

 

Bullcrap.
I agree brake fluid but there is “brake assembly fluid” that is the consistency of silicone gel that is brake fluid compatible. It will hold components in place while assembling. Works very well and available at most auto parts houses.

 

Well, Mr Nickmil, I see that the final word is "Bullcrap". Is that the brand of "silicone gel" that should be used to lubricate the rubber cups on the inside of a wheel cylinder? Since you didn't put a link to a product that could educate me and lift me out of my ignorance, I did a search. I came up with this product https://www.amazon.com/dp/B0018PSAS...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
The product states that it can be used on calipers and rubber parts in brake systems. I was taught by a mechanic and by multiple family member to never use anything but brake fluid on wheel cylinders when assembling, cleaning or honing them. It seems to me, this product, for the application of assembling wheel cylinders is a solution looking for a problem. Will it contaminate and is it compatible with your brake fluid? Since I have never heard of anyone using it for this particular application, who knows? If the cups and the pins fall out of your cylinder and the boot over all that falls off, this snake oil isn't going to fix that.

 

180G ATE Brake Cylinder ASSEMBLY PASTE BRAKE RUBBER GREASE LUBE BREMSZYLINDER | eBay


I have always been told and have used only brake fluid also but this thread made me look. I found the above product and others so it seems to me that other options, besides brake fluid, do indeed exist and have very positive feedbacks. Again, I have no personal experience with anything but brake fluid but Nick has never steered me wrong. I’d give it a go under his suggestion if I was looking for such a product.



Found this too. Not much of a description but the question/answer area makes the products intended use obvious.

https://www.amazon.com/Raybestos-BA...8Q83Q2ZV44M&psc=1&refRID=ZH6ST6GFM8Q83Q2ZV44M

 

Interesting. I would rebuild wheel cylinders and master cylinders long ago, and all I used is brake fluid. Maybe there are more exotic cylinders that are difficult to assemble with regular brake fluid. With this more slippery stuff, perhaps it's easier.

I never found the assembly part difficult - the main issue was honing the cylinder until the rust pits were gone. Even then, they sometimes would not hold a seal for long. Seems like old cars always had water in the fluid, and it would settle in the cylinders. This caused rust at the location of the water drops. Not a problem with wheel clinders until you replace the shoes and locate the pistons further into the bore.

With the Bendix brakes, the cylinders are so cheap that I'd just buy new and throw the old ones in the trash... especially if this is the first time you've relined the brakes and the vehicle is new to you. Probably applies to the Delco brakes too (my J10 for example). The reman master cylinders are likely ok - I've been running a reman master cylinder in my CJ-6 for a decade. These factory remans are bored out and renewed with a steel sleeve, as I understand.

 

The little bit I just read about these products seems to point to stubborn caliper pistons and how these lubes aid in the reassembly of these parts.

I helped my sister's boyfriend with several brake jobs, many many moons ago. He honed and rebuilt the wheels cylinders on 2 Mustangs and used only brake fluid. I think wheel cylinders put up little to no fight during reassembly compared to calipers/pistons.

I just replace the cylinders rather than rebuilding them. Sometimes the lines won't come out of the cylinders and a rebuild in place might be a better option. But I figure that if the lines and fittings are rusted THAT badly into the wheel cylinder, then the line might well be compromised from salt/rust also. At that point, new lines are made and it becomes a bigger project. But I don't like leaving things to chance in the brake system.

 

I too used to hone and rebuild but have taken the easy route in last few years and just buy new cylinders, or calipers.

When I do the brakes on an old Jeep, or any old car I always renew the whole system including new hard and rubber lines, and all cylinders.

I usually don't know what brake fluid type was used by previous owners and with everything new I know it is all good and clean.

 

I'm gonna weigh in here, the last rebuild kit I bought for brake cylinders (about 15 years ago) actually came with a red pasted grease that was listed to lube parts with when reassembly, these came directly from Wagner that way. I have learned a lot from old mechanics, I have been told a lot of wrong crap from old mechanics over the years, I assure you if its made for brakes and sold to you with the kits it's not snake oil.

When I was a kid you couldn't even find assembly lube you just used engine oil, you also knurled guides instead of putting new ones in, times change and so do techniques.

 

I guess they are always coming up with new products but I never have had any problems using brake fluid to lube the bores and cups. I have rebuilt many brake wheel cylinders and master cylinders for drum brakes, but I have never rebuilt a disc brake caliper so I suppose there may be some advantage with the grease on those. I don't know.

For engines we used STP and white grease for pre-lube when I was growing up. I was in my 30s before I knew they actually made "assembly lube".

I don't even know if they still make STP.

 

They do, but if you're counting on it to actually be a ZDDP additive for your flat tappet cams, save your money, it's got less than the modern motor oil you're adding it to. I can't remember where I saw the analysis, but probably bob the oil guy.

 

There are oils with the zinc additives the hot rod crowd uses nowadays. Pre-lube is just for initial start up, and I don't see how it would matter much about the zinc additive in that which will be washed out by the oil in a few minutes of running.

I was just remembering we used STP for pre-lube on valve train parts when building an engine when I was a youngster. We used white grease on the main and rod bearing journals.

 

I ran the customer service and race support for Hayes Disc brakes for many years. Think Harley Davidson and Mountain bikes. I've see a lot of brake systems come back contaminated with all sorts of stuff. Swells the seals up and locks the systems up solid. Even some of the fluids and lubricants that are advertised as DOT 3 compatible will swell the rubber parts. We used Parker Super O Lube to assemble the Master Cylinders and Calipers. the Super O Lube does not affect the rubber so good to go.
Was at a race in Les Gets France and forget my Super O Lube. The closest thing is KY. The pretty lady at the boutique pharmacy didn't speak English, nor I French. Picture thumb and forefinger in a circle, demonstrating with my other forefinger the purpose of the "lube". No need to speak French.