78 FJ40 mushy brakes

[Kmall]

Just to start out, I am not a master mechanic. I muddle through most things with a willingness to learn. I am hoping to use any responses to gauge whether I can attack this myself, or need some help.

While the brakes on my FJ have never been "stop on a dime" material, as of late, they seem to be less responsive. I cannot get them to lock no matter how hard I stomp the pedal. In the last year I did a OME 2.5 inch lift and added 33's. I know that has an impact. The rear brakes were replaced about 2 years ago and the front maybe 4-5 years ago. I have also noticed that the master cylinder reservoir closest to the windshield has been losing fluid. I cannot seem to find a leak in the brake lines and pumping the brakes doesn't particularly make stopping better.

Any thoughts on where to start would be appreciated.

 

[JohnnyC]

drums need to be adjusted... regularly... when did you do it last? 2 years ago?

 

[Kmall]

Thanks for the response!

Yeah would have been two years ago. Just lift the rear and adjust till they are in contact with the drum then back down?

Thoughts on the loss of brake fluid?

 

[tlc762]

Thoughts on the loss of brake fluid?

Could be several things... leaking wheel cylinder-look inside rear wheels/tires and drums, leaking brake line-look for drops/puddles on the ground and dirt/gunk around fittings etc., leaking master cylinder into the brake booster-remove master cylinder and check for fluid in booster.
HTH,
Will

 

[tls3601]

Also possible your calipers up front are frozen, rig will still stop but NOT very well-going thru that right now on my '78. Thread is '76 Brake Components................

 

[Mace]

Commonly the master cylinder will leak into the brake booster. You may want to check and see if that is a concern.

 

[Kmall]

Thanks for the Replies so far.

Mace - what is the least invasive way of checking if it is leaking into booster? I will check FSM as well.

tls3601 - Reading your thread. Very helpful. I am sure I'll be reaching out again. One front caliper looks brand new and the other has a fair amount of rust. They were obviously put in at the same time. Climate out here has not been kind.

 

[Mace]

If the brake master is leaking at all, it should slowly drop when you step on the brakes.

How much does the level is the res drop? Refilling it once a week or?

 

[Kmall]

Seems to hover right around the Min - line. It's been in the garage for most of the winter. I drove it just a couple times over the winter and I have had to fill it two, maybe three times from Min to Max. There hasn't been much driving though. I filled it yesterday so I will pay closer attention. It's parked in a clean garage and the standard oil leaks are easy to spot.

 

[tls3601]

Kmall, yes where I grew up everything rusted and quickly! I don't even know how long my front calipers have been on my rig but all the brake dust and turning front wheels with effort................time for new ones!!!!! Was probably hurting my mileage-ha ha

 

[thebigredrocker]

Did you find your leak? Have you bled your brakes? If the resevoir got too low perhaps some air got in.

Rear drums? Did you get them adjusted?

 

[Racer65]

Thanks for the Replies so far.

Mace - what is the least invasive way of checking if it is leaking into booster? I will check FSM as well.

tls3601 - Reading your thread. Very helpful. I am sure I'll be reaching out again. One front caliper looks brand new and the other has a fair amount of rust. They were obviously put in at the same time. Climate out here has not been kind.

For your first question, you can remove the 4 nuts attaching the MC to the booster and pull the MC away from the booster about an inch or so, without disconnecting the lines. See if there is any sign of wetness on either the booster or MC side. Also visually inspect the booster to see if it's particularly rusty on the bottom side. That's a sign of brake fluid having accumulated there.

Assuming the climate is the same on both sides of the car, either that rusty caliper has been leaking for some time, or the PO only changed one side, which is really bad practice.

 

[Weber Sarge]

An old mechanic's trick to see if a master cylinder is starting to leak into the booster - insert a zip tie down through the vacuum port to the bottom of the booster housing - use it like a dip stick of sorts .
Sarge

 

[Kmall]

These are great tips. Thanks Racer65 and Weber Sarge.

As far as the leak, I have not found it yet, although the fluid has been holding level for a week now. Got out and drove it about 40 miles total this weekend and was stopping closer to what had been the norm. I believe both calipers were replaced at the same time. Just one happens to be rusty. I keep it near the Atlantic in the summer and the salt air has just been murder. Strange that it is only the one, however.

I will see if it has been leaking into the booster per your instructions.

Thanks!

 

[Kmall]

Having gone through a move and remodel, the cruiser sat in the driveway for a couple months. When I finally went to drive it, the brake fluid had emptied again from the reservoir closest to the booster. I refilled it and by the next morning it had drained again. It is leaking with a speed now that makes it a little easier to see where it is leaking from. It appears that it is coming from where the booster meets the master cylinder. I am bringing the cruiser back and will try to tackle this one in the coming weeks myself. As usual, I would love any thoughts, tips, tricks. Also, any suggestions on what and where to buy from. Should I replace the booster and master cylinder both? Rebuild? Replace or repair anything else while I am doing this job?

Much thanks everyone.

 

[tls3601]

I would replace the booster and master but that is just me. I did an OEM master and one of Racer65's boosters. You need to adjust the push rod clearance whenever you replace the booster, they seem to never be in the exactly right spot-ask me how I know!!!!!!! If it is above your ability have a mechanic adjust the clearance-I did and should have done that a LONG time ago. Also check your rear brake cylinders and lines/connections. If there is fluid in there I bet it is DOT3 brake fluid. Differential gear oil can also get in there too-been there as well.........

 

[Mace]

How do you get axle oil into your brakes?

 

[Kmall]

Thanks for the tips. As for the axle oil, I was curious about that too.

So Racer65 for the Booster. Recommendations where to get the master from?

 

[Kmall]

For your first question, you can remove the 4 nuts attaching the MC to the booster and pull the MC away from the booster about an inch or so, without disconnecting the lines. See if there is any sign of wetness on either the booster or MC side. Also visually inspect the booster to see if it's particularly rusty on the bottom side. That's a sign of brake fluid having accumulated there.

Assuming the climate is the same on both sides of the car, either that rusty caliper has been leaking for some time, or the PO only changed one side, which is really bad practice.

Racer - Given that the one caliper is fairly rusty and should probably be replaced, Should I do both at the same time?

 

[emac]

For my 77 I bought new calipers, wheel cylinders, and master from Rock auto. New booster from @Racer65 . None of it was crazy expensive, so my advice is to redo it all and be confident that is done properly. Consider machining drums and discs. I was unable to source any rear drums, and luckily mine had enough metal to resurface.

A couple of things: Bench bleed the master, and read about bleeding/burping air out of the rear cylinders (the design tends to hold air in the cylinder). Bleed system, Adjust the rear shoes until wheel stops spinning then back off a little. Test drive, rear brakes shouldn't lock up first. If they do back them off some.

I did everything except the booster during my rebuild. After I couldn't get the brakes like I thought they should be, I bought the booster. That was the icing on the cake. Many thanks to @Racer65 for supplying a replacement. HTH.