Brake Booster Replacement - a Hint

[SteinOnkel]

Yes, Can be had at your local NAPA

I hate that place. Their markups are ridiculous. And they are almost always staffed by crusty old white dude that seem to know everything better than you do.

[tima01864]

Always been fair to me. Only place I could find in a brick and mortar store that had the fuel lines I have needed. Also the oil filterthey sell for the Spideris excellent/ Wix made for NAPA

[DieselSpider]

Geoff, just a comment on vacuum bleeding the brake lines. I know some people much prefer this over the method of having an assistant press on the brake pedal while you open and close the bleed nipple and look for bubbles. I prefer the latter, and here's why: The threads on my bleed nipples have loosened up due to age, and so pulling a vacuum on that bleed nipple also draws air past the threads that mixes with the fluid coming out, so it's hard to tell what bubbles are due to air in the lines and what are due to thread leakage. When you force fluid out of the lines by pressing the brake pedal, this isn't a factor.

-Bryan

The main issue I have with the vacuum method is that the pumps almost always suck. When they fail, you are stuck with a car that can't be driven, yay.

We flush our brake systems before every trackday, so about 8x per year. The two-person method is the most reliable and cheapest.

An alternative would be the Motive Products Power Bleeder. You connect it to the reservoir, pump up the pressure and go through all corners one by one. The only downside is the price. It's $50 with one cap adapter, but an additional cap is $27 which seems outrageous.

Cheers
Steiny

I have used some MityVac units that have been in service for over 20 years in a pro-environment. They do require occasional lubrication and you can't allow brake fluid to be pumped through them hence the supplied capture can on the kits for bleeding brakes. You only need one person who misuses them to mess them up. Yes accidents do happen and when they do you have to clean the pumps out before the brake fluid has a chance of doing any damage.

Even if someone sucks brake fluid through them or otherwise damages the seals there are inexpensive seal kits available that a heavy user can keep on hand and can be installed in a jiffy. I keep mine sealed in the case so clean and dust/grit free.

[tima01864]

The problem with the brake pump and close the bleeder method. There may not be a helper around. As is usually my case.

[geoff]

thanks for the link MAXM50, I will take a look at it - but I was rather hoping to get an "original" style hose with the threaded union on one end. I guess the consensus is that such a thing is no longer available?
It seems a little strange that the designer chose a hose system with a threaded union on one end, and a push on connexion at the other. This makes no sense to me. Can anyone explain?
Furthermore, whilst using a hose clamp on the barbed end of the hose attachment seems fine, it is not so attractive to me to use a hose clamp on the smooth inlet rail (smooth because I assume I need to cut off the threaded union).

[geoff]

so I am having problems bleeding the rears!. Everything was working well until I replaced the servo!
The rear axle is on stands and I am using a syringe directly on the outlet pipe from the m/c but still I am just getting drips out of both rear slave cylinders. Yes, I know that it looks like it may be the regulator but it is too much of a cooincidence that this just failed whilst I changed the servo.
Has anyone any ideas or trick I can try before i remove the regulator?
regards
geoff

[18Fiatsandcounting]

...I am using a syringe directly on the outlet pipe from the m/c but still I am just getting drips out of both rear slave cylinders.

Geoff, I'm not sure I know what you mean by using a syringe on the outlet pipe from the master cylinder.

I forget what all has been done to your brakes (other than replace the servo), but was the master cylinder replaced?

-Bryan

[tima01864]

The hose looks like one piece, But as the previous said You need to cut the hose away. The threaded fitting remains. I think this is what you are saying.

[SteinOnkel]

I would suggest gravity bleeding. Open up the reservoir, top it off. Crack open the bleeder nipple on one wheel cylinder.

And then go to the park, spend some time with the family etc. Come back and do the other side.

[tima01864]

I would replace the rear brake compensator first. Once you disconnect the lines fluid will pour out.

[geoff]

what I mean Bryan is that I disconnected the rear brake pipe from the m/c, I then put a syringe full of brake fluid on to the pipe. The car is supported on the back axle. I am getting nothing out of either of the rear nipples when I squeeze the syringe
OK, Ok yes, I see this points to the compensator but just before I exchanged the servo the car was safety tested at the test centre and both front and rear bakes checked out fine!
So perhaps a co incidence and the compensator has faile too. I am truly suspicious.

[18Fiatsandcounting]

I am getting nothing out of either of the rear nipples when I squeeze the syringe

But where is the fluid going? It's either leaking past the seals of the syringe, dripping out where you attach the syringe to the rear brake line, leaking out somewhere along the way to the rear of the car, or filling up air space in your rear brake lines or compensator or calipers.

Note that if you have had the rear brakes opened up at some point (replaced or otherwise drained of fluid), it can take quite a bit of effort to refill everything and get the air out. It's not unusual for me to go through a quart of brake fluid to refill and bleed a system that has had the calipers rebuilt, M/C or compensator replaced, etc.

-Bryan

[DieselSpider]

what I mean Bryan is that I disconnected the rear brake pipe from the m/c, I then put a syringe full of brake fluid on to the pipe. The car is supported on the back axle. I am getting nothing out of either of the rear nipples when I squeeze the syringe
OK, Ok yes, I see this points to the compensator but just before I exchanged the servo the car was safety tested at the test centre and both front and rear bakes checked out fine!
So perhaps a co incidence and the compensator has faile too. I am truly suspicious.

What happens when you remove the flexible brake hose from the hard line at the wheel? If the fluid comes out freely from the hard line then the problem is in the rubber line or caliper. You might even have debris plugging the bleeder orifice.

If you do not get any flow directly from the hard line that the rubber hose connects too at the wheel then perform the same test with the rubber hose at the compensator to verify that rubber hose is not plugged.

You may even find some debris had plugged the brake failure light switch and is preventing fluid flow.

Sometimes you just have to follow the flow and disconnect one fitting at a time until you find the failure point where fluid is going in and not coming out.

[geoff]

well, I am very pleased to tell you that using the following procedure my brakes are now fully bled and the pedal feel is perfect. This is what I did in order to nicely bleed the rears which were proving difficult to bleed.; firstly I disconnected from the master cylinder the one pipe which feeds the rear axle. I then used a jar of brake fluid raised high above the bleed nipple on the furthest wheel away from the master cylinder and allowed gravity to very slowly feed fluid via the bleed nipple from the raised jar right up to the outlet of the pipe at the master cylinder. This has the advantage of clearing air from the whole pipe including the end at the master cylinder where the pipe rises into an arch before descending into the master cylinder itself. I must admit that I did have to use a syringe to start (prime) the flow.
Whilst the fluid was still slowly flowing I screwded in the pipe at the master cylinder and opened the bleed nipple at the other rear wheel. This allowed the process to continue, bleeding the second rear wheel.
I then, using the normal procedure of asking an assistant to press the brake pedal, bled the two front wheels.
The pedal feel is excellent. I will take the car out for a run tomorrow. Fingers crossed.

[18Fiatsandcounting]

That's very interesting, Geoff, and if I understand you correctly, you "reverse bled" the rear brake system through the bleed screw back to the M/C. I don't see any downside to this, and my only thought is that I would follow up with a few cycles of the "normal" direction bleeding on the rears just to be sure. But, it sounds like you're good as things are, so I think our work is done here. I'm glad you got this resolved.

-Bryan