Hydroboost slow to return the pedal

[JeepBuilder]

I just had a look at the factory manual and looked through lubrication and maintenance chapter and the brake chapter and did not see anything regarding the power steering fluid type. It does mention the use of DOT 3 brake fluid in the brake system itself. Nothing on the power steering type of fluid. Every other component is mentioned for fluid type. It does mention PS capacity differences depending on model. I am using Redline power steering fluid. It did cure the cold weather issues.

 

[BigPapa]

I found this TSB.

Found this on the Redline website.

It sounds like the Redline fluid meets the specs of the approved Mopar fluid, but I wouldn’t suggest mixing it. I’d do a total flush to remove the OE fluid then go with the Redline.

 

[Ozymandias]

Okay so it should work, I wasn't sure about the material compatibility for let say seal rings and such but this doesn't seem to be the case.

 

[JeepBuilder]

Well, that is interesting. I thought I got most of whatever was in the system out when I changed to redline. I am sure I did not get it all. But it is dirty looking. So I will address that with the upcoming filter and screen clean. I highly doubt the previous owners (and I know one of them) would find the correct information and act on it regarding what fluid to use. Maybe that is why it did not perform well in the very cold weather a couple years ago. I am glad to see the redline has the thumbs up. It did fix my issues earlier. Thanks for posting that information Bigpapa and Ozymandias.

 

[JeepBuilder]

I am still waiting on the hydroboost rebuild kit. They took 8 days to get it out the door. And being 9 degrees this morning means a slow moving thread. I will follow up with the end result when I can.

 

[JeepBuilder]

Well the hydroboost kit arrived. While slow to ship, the kit looks to be the most complete kit out there by word of reviews and different forums feedback. It has really good instructions and looks like a lot of parts. I purchased it from Pirate Jack. When the weather offers a warm day I will pull the unit and take it in the shop for a rebuild. I decided that a rebuild should be done. I am seeing a black tint to my fairly new Redline PS fluid. There is a possibility that is from seal deterioration. I see the lower 40's next week. Here is a link and two pictures of the kit. It is Kit 501. 35 bucks well spent. I will post the rebuild process. Entertainment for what feels like a long winter.

https://piratejack.net/hydro-boost-rebuild-kits/

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[JeepBuilder]

I removed and rebuilt the hydroboost today. I used all of 4 seals and the check valve from that comprehensive kit. Unfortunately I could not replace the two seals on the shaft that connects to the pedal. Even if I cut the shaft and tried to put those small seals in, I suspect they would split since the pedal shaft is huge. The seals are a lot smaller ID. I did not want to go through all that. Now it is nice to have some fresh seals in place, but I can now say I am pretty sure the pedal pivots are the cause. I push the brake pedal with nothing hooked to it, and it is stunning how much effort it takes to pull it back. So the clutch and brake are as tight as can be. I am taking the lower middle of the dash out so I can reach up and pull the pivot shaft. Then drop the arms down for a clean and regrease. I am hoping I don't have to pull the column and entire swing pedal assembly out. I will post up what I find. But now I know the pivots are as tight as they could be. And they should float back and forth with a finger tip. Stay tuned.

 

[JeepBuilder]

It has been 12 and 17 degrees the last several nights. But mid 50's during the day. so, because I am waiting for parts for a T98 4 speed rebuild and a Buick 350 refresh, I decided to get after the pedal assembly. I was able to remove the shaft snap ring, but the shaft was stuck tight as ever. So I removed everything for getting the swing pedals out. And I see I need to clean up some previous owner electrical slop.

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The aluminum swing pedal assembly just about would not come out because of the steering column studs on the firewall. Removing the two lock tighted studs up by the instrument cluster that hold the upper steering column in I was able to get it out. I took the instrument cluster out to install a new clear face I have here. This one is crazed and cracking badly. The previous owner used interior wipes and they just wreck stuff.
So, I could not get the shaft out using a brass drift and a small ball peen hammer. The pedals are tight, way to tight. After using a bigger hammer with no luck and concerns of breaking the aluminum assembly from the impacts, I pressed it all out on the bearing press. I could see it was rusted and no longer working well.

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The forced removal destroyed 2 of the 6 bushings. They were stuck and bonded to the rusty pedal shaft. There are two bushings per pedal and one on each end of the pedal shaft in the aluminum. Part number 4294639 and about 5 bucks each. Ebay was 12 bucks each. So if you are feeling generous... I got mine from rock auto. 6 each at about 5 bucks a piece. And a new brake light switch. I read when you unload the brake light switch plunger, you have to replace them. Dorman has a copy of the bushings and their part number is 74016. I always use OEM parts unless they are inferior. There was one single shim on the shaft assembly. Waiting for parts yet again.

So the shaft was toast. To much rust and it was not cleaning up. I wish I had a piece of stainless but all I had was mild steel. I made a duplicate shaft.
The shaft is .747 in diameter. It is 6.060 long over all length. The snap ring groove is roughly .055 wide but needs to be .623 in diameter at it's depth. The distance between grooves is 5.550 The ends have a chamfer for feeding through the pedal bores. This is in case someone else has the same issue and needs a replacement. I don't think there was enough grease on this assembly. I will be generous with the red synthetic on reassembly. It is not going back in till the pedals swing with a finger tip.

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Anyway, I believe this was my problem. I still put some new seals in the hydroboost. I had the kit and it is actually pretty easy. So when this is all said and done, It should work well. I hope to get out soon, but will wait till they quit with the road salt on the hiways. I will post my end results.

 

[petersonj]

That turned out to be quite the project. Great job on your part!

- John

 

[Topzide]

@JeepBuilder, Seeing as you've a lathe to "play" with for your parts, You should have just gotten some Derlin yo make your bushings while you were at it. It's nice to be able to make some things for projects as you can improve on the design! I've got a small metal lathe that helps me with making bushings for my compact tractors. Have had to turn a couple of pins and some small shafts for a couple of clocks that I own. Great feeling to see the finished part from where it starts at! Great repair write up! This helps shine the light on an issue that may be plaguing others.

 

[BigPapa]

Good job JB. Yeah, that assembly is no fun to get out. When I converted my '95 to a manual I struggled with removing it and finally just pulled the shaft and replaced the pedals. Of course, it wasn't in the shape yours was in.

 

[JeepBuilder]

Thank you guys for the words. I am glad to know it will be fixed. I do have a small lathe. I was given a Jet 10x24 years ago by a friends dad. I cannot even begin to recall how many small parts I have made. Clutch parts for my jeep builds, misc pieces, rubber molds, lots of different things here and there, and even a super small bushing for my Pfaff sewing machine. It is so handy. I am about to make yet again another clutch fork rod pocket on my 1 ton truck build I am almost done with. It gets a lot of use. I'd like a slightly bigger lathe but they like everything else are over priced now. I pondered a different or better bearing. I figured I would see if the OEM bushings are able to be had, and they were, because waiting for a delivery of the new materials and then making the bearings would take longer than I would care for. Torrington bearings would have been nice. I have a lot of stuff apart right now. I prefer to do one thing at a time. But now was the time to fix the dodge since it is waiting through winter for better weather and no salted roads. I see 2nd gen trucks down in town and they are full of holes. My truck is almost like new. It has been a very busy winter in the shop. Keeps me sane.

 

[JeepBuilder]

Still putting things back. I had the column out so I put in a new lower bushing that I had on the shelf. I did have an occasional clunk.
That semi crumpled shim that came out of the pivot assembly was not that. It was a stiff wave washer and it goes under the bushing on the brake pedal's right hand bushing just before you slide the bushing in the pivot tube. I located a picture in the factory manual that showed it's location. The pedals are functioning perfectly. Just like new. I hope to continue today. Got two more inches of snow and I quit yesterday because of hard rain. I am eager to test it out.

 

[Tuesdak]

I read when you unload the brake light switch plunger, you have to replace them.

Play with the old switch and take it apart. You will see how you can overcome this OEM limitation and actually reset it. About as unreliable as GM's brake switches so it doesn't hurt to replace them often.

 

[petersonj]

Play with the old switch and take it apart. You will see how you can overcome this OEM limitation and actually reset it

I did exactly that several years ago. Still running the OEM brake light switch. Don't understand why a wear item like a brake light switch would be engineered as a one-time installation.

 

[JeepBuilder]

Well I had ordered a new one back when I took it apart. Why the heck would they design it that way? It was not expensive. The new one is in. I guess from looking at the manual pins 1 and 2 are the brake switch, pins 3 and 4 communicate with RWAL/ABS and the power control module circuit. Pins 5 and 6 are part of the speed control circuit. No simple on off here. I am getting some good stuff done. I have removed all the no longer used poorly routed wiring from a previous owner, installed a new crystal clear instrument cluster lens as my old one was related to the dash apparently, and moved my turbo boost from the gauge pod above the column to a new Geno's three position pillar mount. I found lots of air in my fuel pressure gauge tube and lots of the antifreeze was gone. It had a poorly seated ferrule. I had to run to town for a new ferrule. Today I hope to recharge the antifreeze in the line with a syringe and get the pillar gauge pod mounted. If all goes well I will put in the wiring for a momentary ground for a high power solenoid that energizes a regulated vehicle charging system for my bigfoot camper. And I can button up this quick (laugh out loud) repair. I have always had the philosophy of repairing a problem, and add one or two things in the process. You always end up having a great running rig in the end. I got a little carried away on this one. I wish to get back to my 1 ton jeep restomod. It is calling. I appreciate all the comments and feedback. This is a great forum.

 

[Ozymandias]

Well that's pretty easy to explain - it's designed like that for easy assembly at the factory to compensate for the mismatch at the pedal assembly.
And it's cheap as dirt so replacement in case of defect is easy.

 

[JeepBuilder]

The brake pedal switch is the only part on the truck that is cheap as dirt. So the truck stops perfectly. The brake action follows exactly what my foot is doing. It releases immediately as it used to. Got all the extras done also. I think I won this one. I think I will call it a day. Many thanks to the TDR crowd.

 

[Ozymandias]

Awesome, and thanks to the rebuild kit you didn't spend to much money for it.

 

[JeepBuilder]

It was 35 bucks from Pirate Jack. Good price. Ok so there are two parts that are reasonable. LOL