Brake Booster Remove and Replace (real time) (1 Viewer)

[sjpitts]

Ok, I am trying to do a quick remove and replace of the brake booster. I am trying to get this back on the road for a New Year's trip. It is a "later" 93 with ABS.

I have been following the advice of LandCruiserPhil's thread Brake Booster R&R and a few others.

The first step here is to unbolt the master cylinder and pull it away from the booster. I have seen where multiple people have said that this can be done without undoing the brake lines from the master cylinder. But this seems impossible. It does not seem like there is enough "give" in the brake lines.

I can easily pull it away an inch or so, but it does not want to come any further-- and certainly nowhere near as far as Phil was able to move his (see his fourth picture in the thread above).

Maybe I am chicken and not pulling hard enough?

Or maybe I am missing a trick here?

Or maybe I should just remove the brake lines? How hard can it be the bleed the system?

Thanks in advance.

Jared

 

[LFD2037]

I've done it twice w/out removing any brake lines. Just pull it towards the front. Don't be a jackass about it but give it a decent, steady pull. Once it's out of the way you pull the booster out after rotating to the perfect position, which I never noted but it'll only come out when turned to the exact correct location.

 

[SUMMIT CRUISERS]

Don't remove the brake lines as @LFD2037 stated above. Just pull the master cylinder forward. The lines will bend and they will bend right back. No big deal. I use a rubber mallet to persuade the booster on the install to clearance the intake. It's a tight fit but a little scratch is all that will happen.

 

[madisonr34]

I just replaced my booster 4 days ago. Heres what I did.
I removed the brake master cylinder in order to remove the booster.
There is going to be contact between the intake manifold and the brake booster when you are trying to pull the booster from the fire wall. I eventually used a pry bar between the fire wall and the booster to get it out.
Install is way easier. Use a rubber mallet to tap the new booster past the intake manifold. Make sure you guide the rod linkage onto the brake pedal as you install the booster.

 

[sjpitts]

Thanks for your help. I took the advice and just pulled a little harder and was able to move the master cylinder back several inches. I then got the brake booster out without too much difficulty. It was a tight fit with the intake but it came out.

I am now onto the step of adjusting the push the rod. I don't have the SST so I figured I would just try and make it match the old the one. I am not sure if there is more to it than that?

And I am assuming that when installing the new booster you don't install the linkage thing first-- wait to install the linkage thing until after the booster is in?

Jared

 

[sjpitts]

Ok, I have determined that the push rod on the new booster is sticking out a bit farther than the old one. But it is not easy to adjust that push rod-- I haven't been able to stop it from spinning. But after some searching I found this method here from HRTROB that I am going to try:

Help! Unable to adjust brake booster rod

 

[madisonr34]

Adjust the rod length before you install the booster but leave the jam nut loose. Once the booster is bolted to the fire wall, you can go under the dash to install the rod linkage to the booster.

 

[sjpitts]

I found a pretty good video explaining how to measure for the proper push rod length. This is on a Nissan Patrol but I betting the process is pretty similar.

I am going to use his technique to calculate the needed push rod length, and compare that number to what was on the original brake booster.

EDIT-- I tried to link to the moment in the video where he starts the push rod calculation but it does not seem to want to let me do that. It is at 32 minutes and 46 seconds. So you may want to fast forward to that point.

 

[LandCruiserPhil]

I adjusted the rod by just sitting the old and new side by side and used a level

 

[LFD2037]

I adjusted the rod by just sitting the old and new side by side and used a level

I think he's asking about the rod that goes into the MC.

 

[LandCruiserPhil]

I think he's asking about the rod that goes into the MC.

Nevermind

 

[alex4640]

I personally think it's a really bad idea to bend brake lines for a bit of convenience. Or for any other reason. You should be replacing all the brake fluid and bleeding anyway. Just my 2 pennies.

 

[sjpitts]

Yes, I am still working on the rod that comes out of the brake booster, not the rod that connects to the pedals. As the guy is pointing too in the preview of the video. I will get to the pedal rod next.

But once again I am stuck. I haven't been able to make that booster push rod screw in. Do I just need to grab the locking nut with the pair of pliers and turn in the push rod? That is what I have been trying to do. Or is that locking nut really a jam nut that needs to be backed off before I can turn in the push rod?

When I read the instructions I assumed that the jam nut was just held by locking threads and didn't need to be backed off-- that if I could hold it in place I could screw in the push rod. But since I haven't been able to make the rod turn yet I am now doubting those assumptions.

 

[alex4640]

Yes, I am still working on the rod that comes out of the brake booster, not the rod that connects to the pedals. As the guy is pointing too in the preview of the video. I will get to the pedal rod next.

But once again I am stuck. I haven't been able to make that booster push rod screw in. Do I just need to grab the locking nut with the pair of pliers and turn in the push rod? That is what I have been trying to do. Or is that locking nut really a jam nut that needs to be backed off before I can turn in the push rod?

When I read the instructions I assumed that the jam nut was just held by locking threads and didn't need to be backed off-- that if I could hold
it in place I could screw in the push rod. But since I haven't been able to make the rod turn yet I am now doubting those assumptions.

That nut is a jam nut. Back it off until you get the rod set and then "jam" or lock the nut back down. When I replaced mine, this side was already set at the right length. Are you sure it needs to be moved in?

 

[sjpitts]

I am not 100% sure that it needs to be moved in. But I do know that sitting on my workbench the push rod on the new brake booster is sticking out 0.67 mm farther than the old brake booster. And I understand that it is better to be little short than a little long. That is why I was going to adjust it in a bit before I installed it.


But from watching the video and reading the FSM and various threads I think the "correct" way to adjust the push rod is to measure the length with the brake booster installed and the engine running to account for the variation caused by engine vacuum-- and then to measure the hole on the master cylinder and make sure that the push rod is just a bit (.25mm?) shorter than the hole.

I don't have the SST, so I was going to try and do this last step with the technique described in that video I linked to above.

Does that make sense? Do you think I don't need to?

Jared

 

[alex4640]

When I measured mine it was "close enough for me". I don't remember the actual measurements. But if you feel yours is too long you should adjust it.

 

[Red Merle]

Adjusting the push rod is not an easy task in my mind. I have spent more time fiddling around with that than just about any one thing on my truck.

This helped me, it starts on Page 57. The trouble is that it moved back and forth without pressure, so it's hard to figure out just exactly where it sits when idling without your pressure.

Good luck!

 

[LandCruiserPhil]

From the installation guide included with a Cardone booster-

6. Install and tighten the master-to-booster mounting nuts per service manual.
IMPORTANT: Ensure that the clearance between the booster and the intermediate push rod and master cylinder piston are according to service manual specification. If the clearance is too large the results will be excessive pedal travel. Insufficient clearance will cause the the brakes to drag or lock up.