Hi all,

So I've had a slow to return brake pedal since I bought the truck a year ago, but I was hoping after a power steering and brake fluid flush it would be better. Well I finally got around to flushing them and so far it's not much if any better. It takes a solid 3 seconds for the pedal to return when the truck is warm and even more when cold. I even took apart and cleaned the valve on the high pressure power steering line at the reservoir. And I used almost 4 qts of ps fluid to do the flush. Now we did only pump the brake twice lightly while doing the ps flush, but it spewed almost a qt of ps fluid just from that so we figured that was good for the hydroboost side of things. Anyway the brakes work great, I'm just wondering if there is anything else I can or should do to help this slow return besides replacing or rebuilding the hydroboost. Another ps and hydroboost flush maybe? I don't want to tackle rebuilding the hydroboost until it's really necessary and right now this isn't a major problem. My vacuum pump and ps pump need resealed first to fix my oil leak lol.

thanks in advance guys!

Leatherman,

Read through this.  It is one of the most concise description and diagnosis list I have seen.http://www.brakeandfrontend.com/operation-diagnosis-and-repair-of-hydro-boost-power-assist-systems/

Rebuilding the Hydro is not bad.  I will try and dig up my old pictures.  Will be offline for a few days, but will check in as I can.

Good luck! Hope this helps

Hag

Thank you! I will read that as you suggest.

So I read it, very informative! The only things I got from it that apply to my situation though, are that maybe the return springs inside are worn out, and I can test for movement of the brake fluid while rapidly pressing the brake pedal in 1 inch. If it doesn't move, then apparently the hydroboost is bad. However, according to the normal operation test, mine is working properly because my pedal does sink and then return when the truck is started. Maybe it's not returning that slow? Maybe my brake light switch is just out of adjustment? I'm going to do the above test when I get a chance and see what happens

Edited March 16, 20169 yr by leathermaneod

Glad you had time to peruse it!

I agree with you, the way I read it, yours isn't "broken".  lol  

Maybe a bit of lube on the pivot?  See if that changes the slow return.  I will try and check mine and think about it.  my travel is so little, I don't know that I would notice a slow return.... 

HTH

Hag

I appreciate the reply! I actually just rebuilt the pedal linkage with grease and new bushings so I know that's not it. It may not really be a problem. The only reason I notice it is because of the light on my brake controller staying on after I take my foot of the pedal. 

I wonder what exactly is wrong with the hydroboost if pushing the pedal rapidly one inch doesn't cause fluid movement. Because just thinking about how my pedal is I'm not sure if it will move the fluid with only an inch of travel...

Edited March 16, 20169 yr by leathermaneod

Mine is the same way and always has been. It's especially noticeable in stop and  go traffic while towing. I'll take my foot off the pedal and a few seconds later feel the trailer brakes release. 

That's exactly why I'm concerned about it. I don't tow much but I don't want to have problems when I do either...The FSM says that slow return can be caused by a restricted return line. I just ordered a new return hose from autozone. Only $22 and the short section of mine is in bad shape anyway. We'll see if that helps but I doubt it.

I've never been all that concerned or really looked into it but if you come up with a solution let us know because it is annoying. 

If I get stuck putting through town I normally just turn the controller down some and wait a few seconds before before gassing it at a stop light. 

All I can say is look at the hydrobooster first.

As for the pedal slow to return it hard to say I've paid any attention to that being I so rarely even press that pedal till I'm in a big city. Exhaust brake gets used quite a bit. I know from bleeding out my system now and then that the full stroke return is slow but normally the usage stroke is so short I don't notice any travel maybe 1/8 to 1/4" of pedal throw.

Ok well thank you very much for the reply. I am looking at the hydrobooster, but I'm not sure how to proceed with it. I don't think a normal rebuild will do anything for it since a leak is not the major issue. BUT, I am very hesitant to buy a new/reman on because I have read quite a few threads of guys replacing them and either getting a bad one, or having the new one not fix the slow return. The weird part is that it seems as though as soon as I take my foot off the pedal the brakes are released(truck seems to move easily). The issue is just that the trailer brake controller stays activated. That makes me wonder if I could somehow adjust the brake light switch. I think my brake pedal has more travel than yours, but its not excessive at all. 

Just now, leathermaneod said:

I am very hesitant to buy a new/reman on because I have read quite a few threads of guys replacing them and either getting a bad one, or having the new one not fix the slow return.

Typically that is because a failed power steering pump typically that has push debris all through the system. Then they replace the hydrobooster without flushing and then end up with more debris in the new hydrobooster. Remember these power steering systems don't have a filter. So any debris has to be flushed out first thing before putting the new hydrobooster and/or power steering gear box into service.

Interesting. Well I just did a flush so I should be good on that, but just to be safe I may do another before replacing it if I decide to go that route. I've pretty much done all the testing I can do, so I just have to make up my mind one way or the other. 

Thanks again!

If I do end up replacing the hydroboost, is there any particular brands I should look for or stay away from?