hydroboost mod on 69' 300

[T1 Woodywagon]

Years ago before we bought the vacuum pump and bendix booster there was a single diaphram booster on the car, and at the time I thought about doing the hydroboost mod because my 98' chevy truck had one, but no one was really doing it back then. Well last summer we had other brake issues so I said thats it I'm changing it all. So here we are.

 

[T1 Woodywagon]

Mid week update; I received the PS pump bracket today and was pleasantly surprised, it is a direct bolt up to the gmc PS pump. Thank you 440 source ! Also received the pressure side -6an fitting for the steering box. Now just waiting on the -6an return fitting for the booster, Amazon said I won't get for 2 more weeks. I'll mount the pump and make the lines this weekend.

 

[T1 Woodywagon]

Got the GM pump mounted today, so will take all my measurements for the new hoses. Also picked up another hydroboost core today for $20.

 

[65sporty]

Mid week update; I received the PS pump bracket today and was pleasantly surprised, it is a direct bolt up to the gmc PS pump. Thank you 440 source !
View attachment 441712

View attachment 441713

It's a Saginaw pump just newer, not a lot has changed on them. Great swap.

 

[T1 Woodywagon]

another update; Its all slowly coming together. I made the new lines at work today, and will get everything installed in the next couple of days after work. I also received the booster return line fitting today too! I should be able to road test this thing on Saturday.

 

[T1 Woodywagon]

All lines are now installed, so later I will fill the PS pump bleed air out of the system and bleed the brakes and hopefully the rain will stop here so I can try this thing.

 

[T1 Woodywagon]

Here's a video from last year when the brakes wouldn't hold

 

[T1 Woodywagon]

Well the hydroboost mod is finished, and I must say very happy with the results. The brakes work excellent. Now I've decided to add an oil cooler in the circuit, so I will be adding that later.

 

[T1 Woodywagon]

I just ordered the oil cooler fan combo for the hydro-boost / PS pump, so when it arrives in a couple weeks I'll add its instal with pics here.

 

[The Goose]

Congrats that’s crazy! Doesn’t look too crowded in there either. Good for you!

 

[T1 Woodywagon]

Update: received the rest of the new parts this week, so will start to instal them today. I bought a cooler fan combo, magnetic ps filter, inline on/off temp switch, and 20' 3/8" braided line kit. I will post pics as peices get installed.

 

[T1 Woodywagon]

Got the cooler, filter, temp switch, and braided lines installed today, now just have to put some other peices back on and wire the switch and we'll test next Saturday.

 

[MoparMcK]

Any updates on how this is performing? I am having issues with my 69 Newport. I installed a 440 with a mild cam. The original booster was bad. So I bought one off eBay. Doesn't seem to work regularly. In gear at the booster it has 5" of vacuum. So I am wondering if the cam is killing the vacuum supply for the brakes. Which is why I am researching the hydro boost option.

 

[CBODY67]

Any updates on how this is performing? I am having issues with my 69 Newport. I installed a 440 with a mild cam. The original booster was bad. So I bought one off eBay. Doesn't seem to work regularly. In gear at the booster it has 5" of vacuum. So I am wondering if the cam is killing the vacuum supply for the brakes. Which is why I am researching the hydro boost option.

With that little vac in gear, that low vac level is lower than almost every power enrichment carb/EFI function I know of. Most of the Holley power valves in stock applications were rated at 5.5" Hg, for example. Getting power enrichment at idle is not good, especially for steady running. How much cam? Do you really need that much cam on the street in a 4000lb+ car?

Just some observations and side issues,
CBODY67

 

[MoparMcK]

With that little vac in gear, that low vac level is lower than almost every power enrichment carb/EFI function I know of. Most of the Holley power valves in stock applications were rated at 5.5" Hg, for example. Getting power enrichment at idle is not good, especially for steady running. How much cam? Do you really need that much cam on the street in a 4000lb+ car?

Just some observations and side issues,
CBODY67

This was just a 440 I had sitting around. It was a quick toss in on a budget. After I put a low deck in my 72 Demon. The stock 383 needs rebuilt.