Just finished my Hydroboost install in a 1990 Mustang (Canadian Cobra) GT. What a job. I searched a lot of forums and here's some new information to help you through. The gold bendix hydroboost accumulator holds 75 ml of PS fluid. That is how much you need to have additional freeboard in your PS reservoir. The gold accumulator is 350 PSI nitrogen. The blue accumulator is 450 PSI. (I used the gold one) The maximum motorsports pedal kit is a win, however, I did not have to drop the steering column as "recommended". Two caveats on not dropping the steering column is that is I did not replace the pedal box to firewall spacers with the MM supplied ones, (the stock ones seem to work fine) and my car is an automatic. Pay attention to the brake switch order of assembly before you take it apart. Make sure you order the correct line kit from MM and to do so you need to find out if you have gotten a master cylinder from a (in my case 2002 musting) that had anti lock brakes or not. There are two models of hydroboosts too depending on hydroboost doner year. Anti lock brake master cylinder has a larger front fitting for the brake line and a larger bore piston than the non anti lock brake donor car. Speaking of doner cars, the 2002 that I got my bendix hydroboost unit from and master cylinder was a tough deal. Rock auto would not ship a hydroboost across the US / Canada border likely due to the compressed gas cylinder. I could not find a rebuilt one in Canada to purchase. Turns out I needed both, the junkyard one for the various fittings and hardware, and a rebuilt one that actually worked. The pushrod, spring and star retainer clip is NOT included with a rebuilt hydroboost. Sorry, I should have measured the darn thing, it would be easy to substitute a rod of some type in place of it. But you would till need the return spring and star clip. Ironically, I found my junkyard master cylinder was junk too and Rock Auto fixed me up with a new one. Later, after installing it with the new master cylinder I found out the hydroboost was junk too (it blocked flow to the PS rack and caused immediate recirculation in the PS pump causing severe fluid overheating in about 1 minute with the engine running) and nothing worked. Amazon to the rescue, finding a Cardone brand hydroboost PN 52-7360 in Texas that they seemed to have no problem shipping to Alberta Canada.
PS Hoses: I looked at 57 different fittings and line kits and was not happy with any of them. So I started looking carefully at the 2002 V8 mustang hoses. By golly, with minor bending, the hydroboost to rack hose fit with no changes. It's two pieces, Edelmann 92105 and Edelmann 80247. You need new miserable teflon rings each time you install either of these hoses, dorman package of two PN 82540. At 2$ a pack, get a couple packs, one was defective and I am glad that I paid 18$ in shipping for several packages not just one. The small teflon seal goes into the pressure fitting on the rack, the large one is used to joint two piece hose as well as the hydroboost and PS pump connection. The factory bends in the factory hose fit nice near the hydroboost end and make for a super clean install. looks factory.
PS pump to hydroboost hose is a little tougher. Buy or salvage a 2002 mustang hose. Edelman 91974. Cut the shorter flexible hose section out of it and toss it. Joint the hose back together using a 3/8 flare union and you have a custom hose that fits perfect. I am actually running the junk yard hoses cause they were just fine. Here is the hose, where to cut it, what chunk to throw away and where to joint it. My editing is so good you might not even see that I cut and paste the end on where it gets spliced.
Another thing you need from the junkyard is the aluminum hydraulic fitting block that connects with a banjo bolt to the hydroboost. A rebuilt one doesn't come with it. Regrettably when the wrecker shipped mine from 150 miles away they only wrapped in saran wrap and the courrier broke the hydroboost return fitting off the adapter block. It's a goofy little fitting but I discovered that an oil pressure gauge 1/8 npt female to nylon line compression fitting will do the job. Once again Amazon to the rescue, use the bottom brass bit in this picture, toss the rest with an oring to the hydroboost aluminum connection block. A 1/8" male npt to hose barb fitting for the hydroboost return line. This is low pressure, a hose clamp is fine on the rubber hose.
Last couple of tips. Use the brake fluid bleeder screws on the side of the brake master cylinder first. Car doesn't need to run to bleed the brakes. I have never had so much trouble bleeding a brake system as this one. Then proceed to each of the 4 wheels. Great time to flush the old fluid from your whole system, just keep bleeding each wheel till it comes out clean.
There are rebuild kits available for the hydroboost, but the pedal connection is pressed and staked into the hydroboost unit so rebuilding it is challenging. Pirate Jack website has kits, I have not bought one from them, but it looks tricky to deal with the staked on pedal rod connecton. One guy one line cut and welded it back together. Looked pretty tricky. I suspect that when they are rebuilt professionally they replace the piston and pedal rod, but good luck finding one to buy.
Overall this was a fairly tricky job, required a fair bit of screwing around with bad junkyard parts and hoses, so so instructions, lots of folklore about bleeding the PS side and not a lot of good information found on line. Hence this post. Hope it helps. As for bleeding the PS pump (I am using the stock 1990 5.0 pump) keep the level above the inlet of the pump or you will never get the air out. Use your starter motor to crank the engine while working the rack side to side and SLOWLY adding fluid. Vacuum bleeding didn't work well, as the gasketed PS pump case would suck air at only 10 inches of vacuum which wasn't helpful. Didn't need the vacuum bleeder once I realized that the hydroboost unit I had from the junkyard was no good. Rebuilt one was much easier to deal with. Cardone actually bench tested the hydroboost before shipping so that was a win. Generally once all the hoses were figured out right it bled fairly easy. The power steering rack had a tendency to overflow the PS pump on hard right turns during bleeding, be careful and patient. Oh, lift the front wheels off during bleeding as you will run the steering back and forth MANY times.
Oh, if you hadn't figured this out yet, the accumulator stores 75 ml of PS fluid and it releases back to the pump AFTER you release the brake pedal, after pushing the brake pedal when the engine isn't running. You get a maximum of three assisted brake pedal operations with the engine off, to get all the accumulator oil out. Each actuation is weaker as the nitrogen pressure drops.
The 75 ml of extra PS fluid stored in the accumulator is a item that I am still working on a fix for, plan A is to extend the filler neck on the PS pump about 1.25 inches with a machined aluminum collar using orings to join the filler neck that I plan to slice off. I read an idea from a post where a guy used a chunk of radiator hose and two hose clamps to extend the volume of the neck but I didn't think that was a very good show and shine solution.
Last thing, there are three wires on the 1990 brake reservoir connector, and two on the 2002 one. connect the two pink wires together from the car harness to the single pink wire on the 2002 brake switch. You did get the connector from the junk yard right? The 1990 wiring would light up the check brake lite if the connector fell off the master cylinder (the reason for the third wire) the 2002 one would not.
PS Hoses: I looked at 57 different fittings and line kits and was not happy with any of them. So I started looking carefully at the 2002 V8 mustang hoses. By golly, with minor bending, the hydroboost to rack hose fit with no changes. It's two pieces, Edelmann 92105 and Edelmann 80247. You need new miserable teflon rings each time you install either of these hoses, dorman package of two PN 82540. At 2$ a pack, get a couple packs, one was defective and I am glad that I paid 18$ in shipping for several packages not just one. The small teflon seal goes into the pressure fitting on the rack, the large one is used to joint two piece hose as well as the hydroboost and PS pump connection. The factory bends in the factory hose fit nice near the hydroboost end and make for a super clean install. looks factory.
PS pump to hydroboost hose is a little tougher. Buy or salvage a 2002 mustang hose. Edelman 91974. Cut the shorter flexible hose section out of it and toss it. Joint the hose back together using a 3/8 flare union and you have a custom hose that fits perfect. I am actually running the junk yard hoses cause they were just fine. Here is the hose, where to cut it, what chunk to throw away and where to joint it. My editing is so good you might not even see that I cut and paste the end on where it gets spliced.
Another thing you need from the junkyard is the aluminum hydraulic fitting block that connects with a banjo bolt to the hydroboost. A rebuilt one doesn't come with it. Regrettably when the wrecker shipped mine from 150 miles away they only wrapped in saran wrap and the courrier broke the hydroboost return fitting off the adapter block. It's a goofy little fitting but I discovered that an oil pressure gauge 1/8 npt female to nylon line compression fitting will do the job. Once again Amazon to the rescue, use the bottom brass bit in this picture, toss the rest with an oring to the hydroboost aluminum connection block. A 1/8" male npt to hose barb fitting for the hydroboost return line. This is low pressure, a hose clamp is fine on the rubber hose.
Last couple of tips. Use the brake fluid bleeder screws on the side of the brake master cylinder first. Car doesn't need to run to bleed the brakes. I have never had so much trouble bleeding a brake system as this one. Then proceed to each of the 4 wheels. Great time to flush the old fluid from your whole system, just keep bleeding each wheel till it comes out clean.
There are rebuild kits available for the hydroboost, but the pedal connection is pressed and staked into the hydroboost unit so rebuilding it is challenging. Pirate Jack website has kits, I have not bought one from them, but it looks tricky to deal with the staked on pedal rod connecton. One guy one line cut and welded it back together. Looked pretty tricky. I suspect that when they are rebuilt professionally they replace the piston and pedal rod, but good luck finding one to buy.
Overall this was a fairly tricky job, required a fair bit of screwing around with bad junkyard parts and hoses, so so instructions, lots of folklore about bleeding the PS side and not a lot of good information found on line. Hence this post. Hope it helps. As for bleeding the PS pump (I am using the stock 1990 5.0 pump) keep the level above the inlet of the pump or you will never get the air out. Use your starter motor to crank the engine while working the rack side to side and SLOWLY adding fluid. Vacuum bleeding didn't work well, as the gasketed PS pump case would suck air at only 10 inches of vacuum which wasn't helpful. Didn't need the vacuum bleeder once I realized that the hydroboost unit I had from the junkyard was no good. Rebuilt one was much easier to deal with. Cardone actually bench tested the hydroboost before shipping so that was a win. Generally once all the hoses were figured out right it bled fairly easy. The power steering rack had a tendency to overflow the PS pump on hard right turns during bleeding, be careful and patient. Oh, lift the front wheels off during bleeding as you will run the steering back and forth MANY times.
Oh, if you hadn't figured this out yet, the accumulator stores 75 ml of PS fluid and it releases back to the pump AFTER you release the brake pedal, after pushing the brake pedal when the engine isn't running. You get a maximum of three assisted brake pedal operations with the engine off, to get all the accumulator oil out. Each actuation is weaker as the nitrogen pressure drops.
The 75 ml of extra PS fluid stored in the accumulator is a item that I am still working on a fix for, plan A is to extend the filler neck on the PS pump about 1.25 inches with a machined aluminum collar using orings to join the filler neck that I plan to slice off. I read an idea from a post where a guy used a chunk of radiator hose and two hose clamps to extend the volume of the neck but I didn't think that was a very good show and shine solution.
Last thing, there are three wires on the 1990 brake reservoir connector, and two on the 2002 one. connect the two pink wires together from the car harness to the single pink wire on the 2002 brake switch. You did get the connector from the junk yard right? The 1990 wiring would light up the check brake lite if the connector fell off the master cylinder (the reason for the third wire) the 2002 one would not.
