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Another Brake Issue

alexgalexg

NAXJA Forum User
Location
Connecticut
So I replaced my master cylinder recently and even had a whole brake system flush done for good measure. There are no leaks in the brake lines or weeping of the calipers or drums. Brakes are also new. But I have A TON of travel before I get any brake power on my pedal. It is consistent and when the engine is off I can pump the pedal and get a good firm pedal... Not entirely sure what is wrong here. It is important to note that this is also a new master cylinder not re manufactured
 
sounds like air in the system.

did you bench bleed the new master?

have you ensured that the new master isn't leaking. I went through 3 on a friends rig before we found a brand new on that didn't leak.
 
In some cases the rear wheel cylinders don't leak enough to drip, but they are the source of air into the brake system. Engine off, you can pump the brakes up, but when running there is pedal travel...
 
The place I took it to did a full flush meaning it was hooked up to a machine with all the bleeders open and it sent pressurized fluid through everything. I see no signs of leaks from the master cylinder or any other place. The only possibility could be inside the drums as someone had stated
 
In particular, you have to "bench bleed" it on a level surface. Once installed the angle of the MC will trap air.
 
I never take my vehicles to shops for reasons like this. I'm willing to bet they did a hack job and that's why. I'm going to go out right now and try the star wheels. If that doesn't work I suppose I will do the job I paid over $100 for myself :bs::yelclap:
Thanks for the tips guys
 
Get some russel speed bleeders (no, I don't know the size because I haven't needed them on the XJ yet), a length of tube that can fit over the nipple and a mason jar (anything that can hold your fluid) and you'll never need a shop to do it for you. This is, of course, after you take the master out and bench bleed it. You could jack the rear end up high enough to make the master level if you don't want to take it off the jeep to bench bleed it
 
You could jack the rear end up high enough to make the master level if you don't want to take it off the jeep to bench bleed it

Good luck with that, I've tried everything(loading docks and land terrain) and never got enough height to level out the MC!
 
Yes considering I have never had a shop do a job right before (and its not like xjs are complicated), I took it to the best shop Ive ever heard of but I still think the problem is their work. Going to go see about a bleeder kit. I did re adjust my drums but they had already been in good adjustment so my work made no difference. Lesson learned, even if you are busy and just don't feel like doing something simple like brake fluid... do it yourself anyways... party1:
Thanks again guys for the tips
 
So I benched the master cylinder and bled the brakes... Brake fluid I got out was darker than that fluid I put in. Now the brakes work great! So for those of you in the CT area, don't ever use Spring Street Auto for ANYTHING. I am a working college student and they not only ripped me off, but could have gotten myself or someone else killed by leaving me with a malfunctioning brake system knowingly. :yelclap::bs:
 
sounds like air in the system.

did you bench bleed the new master?

have you ensured that the new master isn't leaking. I went through 3 on a friends rig before we found a brand new on that didn't leak.

Leaking where?
 
Because I had them do a full flush I did not need to bench the master cylinder

Actually, some MCs must be bench bleed to empty the rear of the piston area as the stroke is not long enough when mounted to purge trapped air in the back dead zone of the cylinder when mounted.

BUt I tired everything know to try and then some on mine I after 5 years I have yet to solve the soft 1.5" little braking power issue on mine. There is thread from last year here with about 300 posts of all the ideas we tried 4-5 times.

Many of the ideas helped and made it better, and usable, but never made it normal like my other jeeps, and they are all renix era jeeps.
 
In particular, you have to "bench bleed" it on a level surface. Once installed the angle of the MC will trap air.

I installed one 10 years ago on my 85 XJ with out a bench bleed and had no problem. But the ones I have had problems with were less problematic when I removed it and bench bleed it, but mine after 5 MCs, all brand new from different OEMs, and after replacing everything but the Combo valve (which I bleed), never solved my problem, the same as his is.
 
Ones that I had this problem with and fixed, were fixed by new rotors, or tightening a loose caliper bolt, or replacing a loose bent one, replacing rear wheel cylinders that were letting air in but not leaking fluid, replacing worn out rear drums, others have reported bad rubber hoses causing the problem, and bad or stuck Combo valves causing the problem, or bad MCs.
 
Have you adjusted your rear brakes yet,I posted this earlier you may have missed it. If the brakes work fine when you pump them you probably not an air problem, you are just moving more fluid,as the calipers stay full of fluid( no return spring) it is taking more than one pump to fill the rear wheel cylinders, if you don't care to try this fix ,or ignore my help that's fine.. Good luck
 
Leaking where?

The new one I just bought was leaking internally so it filled up my booster!

BTW: unless your trying to impress everyone, you really need to learn how to use the "multi-quote" button!
 
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