Bendix Brake Booster

[NOT A T5]

Hello ALL...I had my original Bendix Brake Booster chromed about 30 years ago and it worked fine all these years. All of a sudden I was losing lots of brake fluid, I used DOT 5 silicone fluid, but there wasn't any visible puddles anywhere. That happened about 2 years ago. After I took the Booster out I took off the Master Cylinder Reservoir and fluid dripped out immediately and I replaced the Master Cylinder. What happened was because of the leaking Master Cylinder quite a bit of fluid leaked into the Booster. Emptied the Booster and shipped it to Booster Dewey just recently. They disassembled it and shipped it right back to me and I wire brushed all the rust off, there was a lot of it, especially where the 2 pieces are joined together. I would only recommend to have your Boosters checked out by those guys. As soon as the Chrome Shop calls me to pick up my other parts I will drop off my Booster for chroming. After I get it back I will send it back to Booster Dewey for final reassembly and testing. I just wanted to throw that out there.

 

[NOT A T5]

Another pic!

 

[Stanglover]

I'm NOT 100% sure, but from what I was told, dot 5 silicone fluid is ONLY used in racing situations. I don't believe the rubber parts in ordinary master cylinders will stand up to the silicone and that's why it finally leaked. I realize I could have been misinformed, so don't beat me up if I'm wrong, but unless you are doing extremely hard braking, there is no need for high temp. silicone fluid. I use dot 4 without any issues.

 

[Carolina_Mountain_Mustangs]

I have used the silicone in the past with no issue. It is better because it does not absorb moisture like the others do that makes it much better. Usually if you pull a master cylinder apart you will have rust pits inside that cause the leak. Rust caused by the fluid absorbing. There are companies you can send both master and wheel cylinders to and they put brass liners in to stop it from ever rusting again. Brake fluid is one of the most neglected fluids in a car and should be changed if you check the the strips you can get at parts house. It shows the moisture level and condition of the fluid.

One check I do every time I drive before I leave I put both feet on pedal an press as hard as I can to intentionally blow a seal if it is about to. Our cars have the dual piston but before 1966 or 67 you only had one and when it went you better have a good emergency brake because there is nothing in the pedal.

As my luck would be I have a hole in my brake booster and will need to get it fixed. I did check and O'Riley says they have them but I have not seen in person and do not know if they are same.

Who else has experience with a re builder? I want someone that puts all new in not just fix what it wrong.

 

[Omie01]

My local O'rielly's store was able to send mine off to A1 Cardone, they rebuilt it for me, and I have not had any issues thus far. My .02 cents.

 

[Bill73Ragtop]

Last year when I was in the offices of LEED Brakes (http://leedbrakes.com/) we discussed Dot 5 / Silicone brake fluid. I was in the process of changing a defective booster from my 69 vert where I had installed Dot 5 initially back in 2008 since it was known at the time that it was good for show-type cars since it did not dissolve paint and did not absorb water. This was seen as beneficial for cars that sit more often than not.

The guys at LEED admitted that 20 years ago they were on the bandwagon with everyone else touting the benefits of Dot 5 fluid, but that has changed 180 deg in the past 5-6 years. The reason things changed is that 99% of all seals being made today are not compatible with Dot 5 and will break down / dissolve very quickly. They noted that if you do use Dot 5, your warranty with them is void. Some older systems seem to be maintaining their integrity since the older seals in them are a different composition and apparently resistant to Dot 5.

I use Dot 4 in both my mustangs these days. Last year I flushed my 69 brake lines 3 times with isopropyl alcohol before introducing new Dot 4 fluid. This year I changed the rear axle brake flex line and two front flex lines to braided stainless lines and during the bleeding process I still found remnants of the purple Dot 5 silicone floating the the jar of fluid I used to collect fluid during the bleeding process.

 

[turtle5353]

Another pic!

How much do they charge to rebuild a booster? I swapped my car to disc brakes all the way around but I am still running the non power master cylinder for the drums. I have all the brackets, pedal, booster, master cylinder off the power disc brake 72 donor car but would like to send the booster out for rebuild.

 

[NOT A T5]

About $135 and up plus return shipping!

 

[Carolina_Mountain_Mustangs]

My local O'rielly's store was able to send mine off to A1 Cardone, they rebuilt it for me, and I have not had any issues thus far. My .02 cents.

Thanks for info I will check with them.

Interesting on the DOT 5 sucks that they changed the seals. I think that is what is in my original 1950 Ford that has never had master cylinder or wheel cylinders rebuilt. It sat from 1952 until 1996 in Buffalo NY and when I got it I took the brake system apart thinking there would be lots of rust. Everything was perfect so I flushed and put the DOT 5 in because it just sits. I did not change any of the cups they all looked new. It still has firm brake pedal with seals that are 67 years old. Don't make them like the use to.

 

[Stanglover]

Last year when I was in the offices of LEED Brakes (http://leedbrakes.com/) we discussed Dot 5 / Silicone brake fluid.  I was in the process of changing a defective booster from my 69 vert where I had installed Dot 5 initially back in 2008 since it was known at the time that it was good for show-type cars since it did not dissolve paint and did not absorb water.  This was seen as beneficial for cars that sit more often than not.

The guys at LEED admitted that 20 years ago they were on the bandwagon with everyone else touting the benefits of Dot 5 fluid, but that has changed 180 deg in the past 5-6 years.  The reason things changed is that 99% of all seals being made today are not compatible with Dot 5 and will break down / dissolve very quickly.  They noted that if you do use Dot 5, your warranty with them is void.  Some older systems seem to be maintaining their integrity since the older seals in them are a different composition and apparently resistant to Dot 5.  

I use Dot 4 in both my mustangs these days.  Last year I flushed my 69 brake lines 3 times with isopropyl alcohol before introducing new Dot 4 fluid.  This year I changed the rear axle brake flex line and two front flex lines to braided stainless lines and during the bleeding process I still found remnants of the purple Dot 5 silicone floating the the jar of fluid I used to collect fluid during the bleeding process.

 Thanks for confirming what I thought I had heard on the DOT 5 silicone b/fluid. I was not sure I remembered exactly the reason.

 I too use DOT 4 without issues, but it would be nice if a non-silicone formula could be developed that did NOT absorb water. I replaced all my lines with stainless steel when I did my brake conversion. A SS master cylinder would be nice also! Dot 4 does however, make a good paint remover on most plastic parts, i.e. the rear brake light lenses that I recently posted on.

 

[Stanglover]

About $135 and up plus return shipping!

 I was able to buy one from Cardone through a parts supplier already rebuilt, but unpainted for $140 Can a couple of years ago. Perhaps they are still available.