Stroverlander
Adventurer
Boost Leak...
Playing catch up once more...
Noticed the Hydroboost had been weeping power steering fluid for a bit as they all seem to do eventually so looked into replacement options. $200+ for a rebuilt/reman unit or $400+ for a new replacement seemed suboptimal so researched repair options and came across these Hydroboost rebuild kits from: http://piratejack.net/hydro-boost-rebuild-kits (also on eBay).
After researching, it appears most Hydroboost units are similar across different makes/models and use the same seals, etc. I found a couple of decent rebuild threads from other forums while searching on the line and so decided to give it a try myself and ordered Kit-501 (2771004) Hydro-Boost Repair Kit from Pirate Jack.
I kept my good eye open for his delivery ship only to be slightly disappointed when delivery was made by USPS. After questioning the delivery driver for a minute, I placed my sword back in its scabbard, tucked my eye patch away, let the driver go and muttered, "Arghh matey, it's on!" to myself as I scampered away. Okay, so I didn't.
If you don't know, the Hydroboost unit replaces the usual vacuum power brake assist in many vehicles with an accumulator based on power steering fluid/pump pressure allowing for a some brake assist in the event the vehicle engine stops. The Hydroboost unit itself is attached to the brake master cylinder, or rather the brake master cylinder is attached to the Hydroboost unit.
You can see the Hydroobost under the master cylinder here, with the silver accumulator reservoir to the left. The first steps were to remove unbolt the fuse box and p/s reservoir to gain some room to remove the power steering lines from the Hydroboost unit.
Power steering reservoir moved off to the side and fluid hose removed, p/s lines disconnected and draining fluid while trying not to make too much of a mess.
I don't have photos so included this parts breakdown image but the master cylinder is bolted to the front of the Hydroboost unit with two studs and nuts which need to be removed in order to separate the Hydroboost from the master cylinder. Other than unbolting the master cylinder from the Hydroboost, nothing brake related needs to be disconnected so no brake fluid or brake bleeding required.
Removal of the Hydroboost unit requires unbolting the unit from inside the vehicle. With the lift and lack of clearance with door opening, I removed the driver's seat in order to contort myself enough to remove the four nuts retaining the Hydroboost unit. I also had to remove the metal clip on the brake pedal with a flat blade screwdriver and remove the brake switch and pushrod from the brake pedal. Good times...
So with the brake master cylinder unbolted from the Hydroboost unit and unbolted from the firewall, it's time to remove the Hydroboost unit. Ha! Easier said than done, it's a tight squeeze... I wrangled around for a bit and managed to tuck the master cylinder below the Hydroboost (frank above the beans...) but what really helped in the end and gave enough clearance for everything was to remove the airbox assembly and radiator fan shrouds. I tinkered with the upper radiator hose to gain some additional space.
In the end, the Hydroboost was free and I started trying to figure out just how I was going to rebuild this sucka. But first I sprayed it down with brake cleaner and took another photo.
Originally, I was all set on doing a complete tear down and rebuild until I realized that this type of Hydroboost pushrod assembly would require cutting and welding to do so. So I settled for basically a re-seal of the Hydroboost unit which is all that was really necessary anyway.
The five bolts holding the Hydrooboost assembly together are torx head screws and I didn't have the appropriate socket but a 10mm socket worked well enough without damaging or stripping the screw heads. While I feel confident I could do this job several times (hopefully don't have too!) without damaging the screw heads with a metric socket, I recommend picking up the correct Torx socket. I would have but it was getting late and I didn't want to make another trip the auto parts store.
With the five bolts removed the unit can be separate fairly easily and more fluid will drain out.
As the unit comes apart, keep an eye on what parts go where, it's not super complicated or anything but helps on assembly.
Inside this half of the assembly in the middle of the cylinder is a seal that needs to be replaced.
There it is. I used a pick and small flat-blade screwdriver to remove and it came out easily. Be sure to note orientation of the seal, the seal lip faces up (or towards pressure side) in this instance.
Here is what is included in the Pirate Jack Hydroboost repair kit. Since not doing a complete rebuild and only a reseal, turns out only a few of the seals in this kit are necessary so no need to order the more expensive rebuild kit, the slightly cheaper 50 (2771004X) Hydro-Boost Repair Kit will suffice.
Comparing the seal I removed on the left to the new seal on the right. Looks good to me, so lubed with fresh power steering fluid and installed in seal groove with seal lip facing up.
The “other” half of the assembly, I replaced that figure 8 looking o-ring as well. Pretty straightforward.
And... basically that was it. I lubed everything with fresh power steering fluid and made sure all the parts were where they should be and fit the two halves back together. It was a little tricky but not too bad. I didn't force anything and made sure the end of the pushrod was seated and centered in the star washer/o-ring at the bottom.
I wanted to replace the o-ring on the accumulator reservoir but it was too long to fit in my vise so I couldn't compress it to remove the clip but it turned out to be okay. The kit does include an o-ring for this though so if I have to do it later I can.
Installation really was pretty much the reverse of removal. I filled the power steering system with fluid and turned the wheels back and forth several times then primed the Hydroboost by starting the engine and pumping the brake pedal about 20 times then bled like normal.
So for about $40 in parts I re-sealed the Hydroboost unit and it's been leak free and functioning like it should.
I am currently searching for an alternative to the $50 per 10-pack of GM 26001594 power steering line o-rings. I've been using generic metric o-rings from a kit I have but they are slightly off dimensionally and so they tend not to hold up over time. The dimensions of the GM o-rings are 7.65mm id X 1.63mm section and trying to find aftermarket alternative that are resistant to p/s fluid...
Beyond that, more catching up to do – front end revisit, new shoes, etc and happy holiday to all.
Playing catch up once more...
Noticed the Hydroboost had been weeping power steering fluid for a bit as they all seem to do eventually so looked into replacement options. $200+ for a rebuilt/reman unit or $400+ for a new replacement seemed suboptimal so researched repair options and came across these Hydroboost rebuild kits from: http://piratejack.net/hydro-boost-rebuild-kits (also on eBay).
After researching, it appears most Hydroboost units are similar across different makes/models and use the same seals, etc. I found a couple of decent rebuild threads from other forums while searching on the line and so decided to give it a try myself and ordered Kit-501 (2771004) Hydro-Boost Repair Kit from Pirate Jack.
I kept my good eye open for his delivery ship only to be slightly disappointed when delivery was made by USPS. After questioning the delivery driver for a minute, I placed my sword back in its scabbard, tucked my eye patch away, let the driver go and muttered, "Arghh matey, it's on!" to myself as I scampered away. Okay, so I didn't.
If you don't know, the Hydroboost unit replaces the usual vacuum power brake assist in many vehicles with an accumulator based on power steering fluid/pump pressure allowing for a some brake assist in the event the vehicle engine stops. The Hydroboost unit itself is attached to the brake master cylinder, or rather the brake master cylinder is attached to the Hydroboost unit.
You can see the Hydroobost under the master cylinder here, with the silver accumulator reservoir to the left. The first steps were to remove unbolt the fuse box and p/s reservoir to gain some room to remove the power steering lines from the Hydroboost unit.
Power steering reservoir moved off to the side and fluid hose removed, p/s lines disconnected and draining fluid while trying not to make too much of a mess.
I don't have photos so included this parts breakdown image but the master cylinder is bolted to the front of the Hydroboost unit with two studs and nuts which need to be removed in order to separate the Hydroboost from the master cylinder. Other than unbolting the master cylinder from the Hydroboost, nothing brake related needs to be disconnected so no brake fluid or brake bleeding required.
Removal of the Hydroboost unit requires unbolting the unit from inside the vehicle. With the lift and lack of clearance with door opening, I removed the driver's seat in order to contort myself enough to remove the four nuts retaining the Hydroboost unit. I also had to remove the metal clip on the brake pedal with a flat blade screwdriver and remove the brake switch and pushrod from the brake pedal. Good times...
So with the brake master cylinder unbolted from the Hydroboost unit and unbolted from the firewall, it's time to remove the Hydroboost unit. Ha! Easier said than done, it's a tight squeeze... I wrangled around for a bit and managed to tuck the master cylinder below the Hydroboost (frank above the beans...) but what really helped in the end and gave enough clearance for everything was to remove the airbox assembly and radiator fan shrouds. I tinkered with the upper radiator hose to gain some additional space.
In the end, the Hydroboost was free and I started trying to figure out just how I was going to rebuild this sucka. But first I sprayed it down with brake cleaner and took another photo.
Originally, I was all set on doing a complete tear down and rebuild until I realized that this type of Hydroboost pushrod assembly would require cutting and welding to do so. So I settled for basically a re-seal of the Hydroboost unit which is all that was really necessary anyway.
The five bolts holding the Hydrooboost assembly together are torx head screws and I didn't have the appropriate socket but a 10mm socket worked well enough without damaging or stripping the screw heads. While I feel confident I could do this job several times (hopefully don't have too!) without damaging the screw heads with a metric socket, I recommend picking up the correct Torx socket. I would have but it was getting late and I didn't want to make another trip the auto parts store.
With the five bolts removed the unit can be separate fairly easily and more fluid will drain out.
As the unit comes apart, keep an eye on what parts go where, it's not super complicated or anything but helps on assembly.
Inside this half of the assembly in the middle of the cylinder is a seal that needs to be replaced.
There it is. I used a pick and small flat-blade screwdriver to remove and it came out easily. Be sure to note orientation of the seal, the seal lip faces up (or towards pressure side) in this instance.
Here is what is included in the Pirate Jack Hydroboost repair kit. Since not doing a complete rebuild and only a reseal, turns out only a few of the seals in this kit are necessary so no need to order the more expensive rebuild kit, the slightly cheaper 50 (2771004X) Hydro-Boost Repair Kit will suffice.
Comparing the seal I removed on the left to the new seal on the right. Looks good to me, so lubed with fresh power steering fluid and installed in seal groove with seal lip facing up.
The “other” half of the assembly, I replaced that figure 8 looking o-ring as well. Pretty straightforward.
And... basically that was it. I lubed everything with fresh power steering fluid and made sure all the parts were where they should be and fit the two halves back together. It was a little tricky but not too bad. I didn't force anything and made sure the end of the pushrod was seated and centered in the star washer/o-ring at the bottom.
I wanted to replace the o-ring on the accumulator reservoir but it was too long to fit in my vise so I couldn't compress it to remove the clip but it turned out to be okay. The kit does include an o-ring for this though so if I have to do it later I can.
Installation really was pretty much the reverse of removal. I filled the power steering system with fluid and turned the wheels back and forth several times then primed the Hydroboost by starting the engine and pumping the brake pedal about 20 times then bled like normal.
So for about $40 in parts I re-sealed the Hydroboost unit and it's been leak free and functioning like it should.
I am currently searching for an alternative to the $50 per 10-pack of GM 26001594 power steering line o-rings. I've been using generic metric o-rings from a kit I have but they are slightly off dimensionally and so they tend not to hold up over time. The dimensions of the GM o-rings are 7.65mm id X 1.63mm section and trying to find aftermarket alternative that are resistant to p/s fluid...
Beyond that, more catching up to do – front end revisit, new shoes, etc and happy holiday to all.
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