hydroboost question

[atxM1028]

Hi guys,
Im new to the forums and have a question I was wondering if anyone could help me with. I have an 84 m1028 that needs a new brake booster (i think). sometimes when im driving and i brake/turn at the same time the power steering seems to go out. The booster is also leaking in down the firewall inside the cab. If it is the brake booster do i need to bleed brakes? if so any input on that would be awsome. I posted some pictures of the truck (unfortunately the pictures are retardedly large, ill try to fix that, but check it out.) Also it has a 6.5T. I dont think that would effect the brakes at all, if it has dot 3 in it would that make it act the way it has been?

 

[gasser]

Yup - you need a new hydroboost. I got mine from AutoZone for about $100 (M1009) - however your truck's unit maybe more - and different.
Welcome!

 

[M1028A1ShelterCarrier]

I had the same issue for my M1028. Do a search on "hydraboost" for several post. For the M1028, the cheapest I have found it is $150 at Kragen

http://www.partsamerica.com/ProductDetail.aspx?mfrcode=A1C&mfrpartnumber=527307&parttype=250&ptset=A

 

[TOBEXA]

so i have the same hydraboost problem, can anyone give a detailed step by step on how to remove and fix it? i got a rebuild kit, but for $150 i can buy it new? what is the part #? chevy dealer wants $600 for it.....loooooooooooooooooooooool

 

[jwaller]

I had the smae issue with my hmmwv. turns out I had to rebuild the power steering pump. when you ask both systems to work at the same time it taxes the pump anf mine couldnt keep up. new pump and all is well.

 

[CCATLETT1984]

I just wanted to add, yes the m1009 hydroboost unit is different then the others. All of the truck cucv's use the same part number hydroboost unit, its the same as the civilian K30 hydroboost unit.

 

[papercu]

brake

If you rebuild or replace you might want to think about flushing the DOT 5 and go back to the DOT 3.
It take awhile to refill with DOT 5 AND keep the air bubbles out of it and as long as it is driven, DOT 5 is not better. Wayne

 

[Barrman]

RE: brake

As far as the actual replacement. Unbolt the brake master cylinder from the booster and slide it forward a little. You can do this without kinking the brake lines if you are careful.

Mark or label or take a picture of the hoses for the hydroboost. Undo them and then undo the 4 bolts that hold it to the firewall. You will also have to go under the dash and disconnect the pushrod from the brake pedal. Take a patience pill before you do this, since sometimes you will almost have it off and then a neck muscle will cramp and you will have to move. Same goes for the 4 bolts that hold the booster to the firewall. Other than that, it is a simple remove and replace deal.

Then you need to bleed it. The power steering part that is. The brakes themselves should be still sealed since you didn't mess with them. Put the front end on jack stands, fill if with fluid, turn the wheel lock to lock each direction a few times with the engine off. Check the fluid in the pump. Then fire it up and do the lock to lock thing. Look at the fluid. Foamy fluid means air is still in the system. check the fluid level and do it again. That is how the book says to do it. I have found if I walk away from it for an hour or so after the first running test, most of the air goes away and no foam shows up when I try it again.

 

[TOBEXA]

the master cylinder has 2 reservoir's....do they both contain brake fluid?

 

[TOBEXA]

damn i think i just messed it all up

 

[TOBEXA]

can you send a link to the correct part #? for a 1009

 

[uh60]

you can download TM's thay are how to books. They will tell you how to work on your truck.

 

[TOBEXA]

where at?

 

[papercu]

where

At the top of the CUCV forum page is a sticky'd post that has all of the manuals for the CUCV.

 

[TOBEXA]

RE: where

thanks a bunch Wayne

 

[TOBEXA]

is this the correct master cylinder for the m1009......? i'm an idiot..........it was not the hydroboost. lmao
http://www.autozone.com/R,APP15314/...partType,00007/shopping/partProductDetail.htm

 

[acetomatoco]

The brake master cylinder has two chambers, one for front brakes and one for rear.. The hydroboost uses the power steering pump and its lubricant... do not use brake fluid in the hydroboost. it is fed by the power steering pump... Check your LO for the proper fluid. The units are different M1009 vs all the others... Chev part #s are for the D1 15521935 and the D3 14055057. Before the big expense of replacing the hydroboost, I would suggest a drain and flush of the power steeering system and its associated brake booster and a refill with new fluid...