Hydra-boost brake install issues in C3 vette

legerwn

Active Member
I installed a hydra-boost brake booster in my car a while back and have had issues with it since the install. I get a good bit of groaning form the pump and the booster gets hot, I’ve tried a few things to resolve it.

I’ve done a good bit of research on the internet and actually stumbled across a tech write up by who I believe is someone from Hydra-tech brake systems. He described a couple issues in detail that I’m experiencing, groaning and push back on the brake peddle when depressed and heat buildup in the booster.

He explains that to much pressure on the return hose will cause the booster to build a lot of heat and will cause a slow peddle return once depressed.

He recommended staying with the 2.0 to 2.4 gpm from the pump as GM did.

He recommends -6 AN (3/8”) lines for the supply and return lines and ½” (minimum) for the line from the remote reservoir to the pump and that if anything smaller was used for the line between the pump and reservoir the pump will cavitate and always run noisy.

I decided since I had my system apart due to line rupture I would try and address as many of his recommendations as I could.

I took my remote reservoir apart and took a close look at all the fittings and lines. The outlet of the reservoir is a 3/8 NPT to -10 AN fitting, first issue. The 3/8 NPT fitting is too small for the supply to the pump per his recommendations of no smaller than ½”. I’ve checked and have room to drill and tap to ½” pipe to gain the recommended size and will install a -10 AN to ½” NPT adapter.

Steering3_zps90c5de11.jpg


Reservoir Return line fitting size (drill bit inserted into fitting) and the reservoir to pump fitting (-10 AN to 3/8" NPT);

Steering7_zps56f2e073.jpg


The pump discharge is -6 AN PTFE SS lines with an internal diameter of .293” (a little below the recommended 3/8”). The returns form the R&P unit and the Hydra-Boost unit is also -6 AN line and is tied together with a Tee at the reservoir, not exactly what he recommends but close.

Steering2_zpsc6fd86fe.jpg


Distribution fitting in reservoir;
Steering6_zps8d875bcd.jpg


On the internal of the reservoir is a distribution fitting with an internal diameter of .247” well below the recommended 3/8”. I believe this fitting is one of the main causes of the pump groaning, the reason for the heat build up in the booster and the slow return of the brake peddle which is caused by to much pressure in the return line to the reservoir from the booster. To resolve the issues with the return line I plan to remove the OEM distribution fitting and fab my own distribution nozzle for the reservoir. If the restriction was closer to the steering gear and away from the reservoir (Tee) it would not effect the booster operation.

Steering1_zpsffab3b7b.jpg


Reservoir Return line fitting size (drill bit inserted into fitting);

Steering7_zps56f2e073.jpg


He also recommends using a remote reservoir with a separate return for the Hydra-boost to eliminate the issue of to much pressure in the return line along with a reservoir with an internal filter for correct de-gassing of the steering fluid.
I’m going to weld a bung on the side of the reservoir or drill and tap a 3/8" NPT hole for a separate fitting in case the new distribution header don’t resolve my issues I can move the return from the booster to its own rout.

He explains that the booster is an open center hydraulic device meaning the fluid flows freely to the booster and own to the steering gear until the brakes are applied.

From what I can find on the net the steering gear is also an open center device meaning the fluid form the pump flows through the gear and back to the reservoir without obstruction until the steering wheel is turned and force is applied to the torsion lever in the gear. This being the case than the return line will need to be sized to flow the pump output flow without restriction. So if the fittings at the reservoir cause restriction than there will be pressure on the return line causing issues with the booster. This would support having a dedicated return fitting at the reservoir for the booster.

One other issue he explains is that the reservoir has to be vented at the cap. If the reservoir is allowed to build pressure from thermal expansion enough pressure can build in the return line and cause the brakes to self apply.

I may have to replace the reservoir if I can't work these issues out. The reservoir I have came with the Zoops serpentine drive unit I have on my engine.

Right click on the photo's to see full view

Anyone else have this type of issues with their Hydra-boost install?

Neal
 
I had more time tonight to look at a few more things with my steering system.

I pulled the fitting out of the pump inlet to see what the internal diam of this fitting was. Turns out they used a fitting with a reduced internal diam of .390”as seen below (fitting to the far left).

Steering8_zpsbb1ebcdd.jpg


The below pic is of the fittings used in the plumbing between the reservoir and the pump inlet. I’ll be drilling and tapping the outlet of the reservoir (middle) from 3/8” NPT to 1/2” NPT to achieve the required ½”.

Steering8_zpsbb1ebcdd.jpg


The pic below is of the reduced internal diam in the current fitting (-10AN to 3/8” NPT) at the outlet of the reservoir (see the shoulder).

Steering10_zps14339d07.jpg


The internal passage of the pump at the inlet is also reduced in size .383”, not much I can do here until I see if the upgrades will resolve my pump issues. If I still have issues I’ll remove the pump and port the inlet to increase the port size. The reduced inlet can be seen in the pic below. I had to use a mirror to get the pic so it’s a little hard to see.

Steering9_zps25fca994.jpg



The pump is a GM Type II pump with remote reservoir used on a number of OEM cars today; Zoops fits it to their serpentine setup. I’ll be pulling the outlet flow orifice to check the size per the tech article. It should be in the .125” area to supply the required 2.0 to 2.4 gpm flow.

Indy, I found paint on my computer and tried my hand at adding text to the pics to help out.

This setup is on my 77 vette,

Neal
 
legerwn said:
Indy, I found paint on my computer and tried my hand at adding text to the pics to help out.

Neal
Neal,

Thanks for taking the effort/time to annotate the pictures, it sure makes it easier to follow along and understand what's being said.

I know everyone else will appreciate it also.

 
legerwn said:
Indy, I found paint on my computer and tried my hand at adding text to the pics to help out.

Neal

can either of you computer savvy ,highly skilled individuals, explain to an old geezer, how you go about posting a typed box of info in your pictures using paint?
a step by step guide for computer skill lacking guys would be great! (computer illiterates)
(I know how to get into {PAINT} but other than hand drawing lines or circles, arrows etc. its not been overly useful to me so far)
 
grumpyvette said:
legerwn said:
Indy, I found paint on my computer and tried my hand at adding text to the pics to help out.

Neal

can either of you computer savvy ,highly skilled individuals, explain to an old geezer, how you go about posting a typed box of info in your pictures using paint?
a step by step guide for computer skill lacking guys would be great! (computer illiterates)
(I know how to get into {PAINT} but other than hand drawing lines or circles, arrows etc. its not been overly useful to me so far)

1) For me I right click on the pic I want to add text to and chose open with Paint, the pic should open in a new window in the Paint program.

2) From there I click on the A on the left side toolbar for text, once the A is selected right below the A will be two boxes with some objects in them.

3) You select which one you want, form what I can tell this either opens the text box with a white background or opens the box with a transparent background.

4) Than I draw a box the size I think I may need based on the amount of text I may add. Once the box is drawn I right click in the text box and open the “Text Toolbar”. The text toolbar will open and allow you to select the size and type of text you want.

5) Than click on the straight line tool in the toolbar on the left side of the screen and select the large line on the bottom of the toolbar.

6) Then at the bottom of the page will be the color selection for the line color, you select any color you want to. Once the color is selected you can draw a line from the area of the pic you want to attach to the text box.

Hope this helps,

Neal
 

I still like PaintNet. I did the photo below in PaintNet.

It has unlimited UNDO.
It has arrow heads for your lines.
I will compress the file 8-10 times smaller.
It can change the size of your image so others don't have to page sideways to see all of it.

I would only download it from my link, as they do make it confusing when it comes to getting the software without things like AOL Toolbar or Amazon Toolbar....etc.

https://dl.dropbox.com/u/7908335/Paint.NET.3.5.10.Install/Paint.NET.3.5.10.Install.exe



Go here for more info and links to tutorials. You will have to page down.

viewtopic.php?f=25&t=5595

 

Attachments

  • PaintNetWindow.jpg
    PaintNetWindow.jpg
    48.9 KB · Views: 262
We’ll I’ve decided to go ahead and plumb the booster return to its own fitting. I was going to keep the returns from the steering gear and the booster together to see if that was an issue before I move it to its own fitting on the reservoir for verification but don't want to remove the steering fluid just to move it if it don't work out

I built the new distribution header for the reservoir and bored the pump inlet fitting to a full .500” internal diarm.

Steering13_zps07b9322c.jpg


The pump with the fittings installed;

Steering11_zps0f4222ab.jpg


The new distribution header installed in the reservoir

Steering12_zps8cf01c3e.jpg


I’m waiting on the new hose ends for the line between the reservoir and pump to come in so I can finish plumbing that side of the system.

I’m still trying to decide if I want to weld the new fitting for the booster return onto the reservoir or it I want to drill and tap a hole for the fitting.

I don’t have the drill bit for the ½” NPT tap or the drill bit for the 3/8” NPT tap so I’ll need to locate and purchase them to finish.

Everyone is closed for New Years today so it’ll be tomorrow before I can proceed,

Indycars; I've read through your link on pic taking and camera handling, great post. I'm doing a better job with the focus

Happy New Year to all, and hope you had a good time last night,

Neal
 
legerwn said:
Indycars; I've read through your link on pic taking and camera handling, great post. I'm doing a better job with the focus

Happy New Year to all, and hope you had a good time last night,

Neal

Glade you like the post. Don't be afraid to take lots of pictures, then delete ones that you don't like. I've deleted about half of the 3000 pictures that I've taken since joining the forum.

Didn't make it to midnight, but that's ok......Happy New Year!

I'm curious since I can't tell for sure. Is the distribution header pulling fluid or pushing fluid thru it??? Another words, is the distribution header the inlet to the pump.
 
This is a very interesting thread on the GM Hyrda- Boost & modifications for better performance.
Thanks for sharing.
I will continue to follow reading as you progress on your project.
 
Indycars said:
legerwn said:
Indycars; I've read through your link on pic taking and camera handling, great post. I'm doing a better job with the focus

Happy New Year to all, and hope you had a good time last night,

Neal

Glade you like the post. Don't be afraid to take lots of pictures, then delete ones that you don't like. I've deleted about half of the 3000 pictures that I've taken since joining the forum.

Didn't make it to midnight, but that's ok......Happy New Year!

I'm curious since I can't tell for sure. Is the distribution header pulling fluid or pushing fluid thru it??? Another words, is the distribution header the inlet to the pump.

The distribution header is on the return side to the reservoir from the booster and steering gear, its to direct the returning fluid away form the outlet of the reservoir to the pump.

Neal
 
Not much to update on here,

Been waiting on Summit to send new -10 AN fittings, when they did arrive they were two different colors so I sent them back.

I’ll purchase a hose from a different vendor and install it when it arrives.

The below pic is of the new dedicated return fitting for the hydra-boost installed in the reservoir.

Steering15_zpsef42a5f6.jpg


Neal
 

Did Summit send two different brands or were they the same??? Are they coming from Summit again?

When you get the fittings, will you have everything you need to finish?

Looks like a very clean installation!!!

 
Indycars said:

Did Summit send two different brands or were they the same??? Are they coming from Summit again?

When you get the fittings, will you have everything you need to finish?

Looks like a very clean installation!!!


The fittings were the same part number and brand but different colors,

I ordered the new parts off ebay this go round

This hose is the last part I need to finish the steering

thanks
Neal
 
One other thing that the tech mentioned was that the type of power steering fluid can also help. He indicated that there are a few that he has seen help with the foaming and groaning issues and they were Lubegard from NAPA (Lubegard makes an additive and a power steering fluid) and synthetics are also a good option to help with foaming and pump groaning.

I read in another article that GM power steering fluid was also a good fluid for a noise pump while using the Hydra-boost system.

He strongly recommends that you do not use transmission fluid in the power steering system.

Neal
 
Well I got the pump inlet hose installed and started the car up to hear the same noise from the brakes and steering, bled the system a couple times, brought the system up to temp and let it cool off a couple times and the brakes are a lot better now. The brake peddle feels more like my Denali which has Hydro-boost brakes and its not noisy anymore but the steering is another issue.

The fluid has metal flakes in it so I started trouble shooting. With the steering wheels off the ground there are hard spots in the rack and pinion. I put the car on the lift and disconnected the tie rods and gave it another try, still have the hard spots. It sounds as if the fluid is going through an orifice than it quits and does it again while turning the steering wheel with the engine off. I’ve ordered a replacement unit so I’ll have to wait on it to take a test drive.

Right now I’ll say that the brakes are much improved but the real test will be once I have the car back on the road and take it for a test drive.

Most installation guides for the Hydro-boost say to give the system up to 500 miles to allow all the micro bubbles to escape. I noticed the accumulator acting funny until all the air was out. Whit air in the accumulator it causes the peddle to kick back when you apply the brakes. I think this is due to the accumulator trying to pressure up with brake fluid but due to the air it can’t.

The accumulator pressures up when the peddle is pressed when the car is started, it diverts pressurized fluid into the accumulator and a check valve prevents it from escaping. If there’s air in it or if the check valve leaks, the peddle when pressed will travel down and than kick back once the accumulator is pressured up, then the brakes will apply. It'll give you an uneasy feeling when this happens while driving the car.

I’m going to do a good flush of the system to try and get all the metal flakes out of the steering system and hope the pump and Hydro-boost system is not damaged.

Neal
 

Was the metal there all along or did it just become a problem after putting it back together this time?

 
its been a little while since I checked the fluid and the last drive it blew a hose and pumped all the fluid out.

The last time I looked the fluid was fine.

Neal
 
Well I got the replacement rack and have it installed; there was a small piece of metal stuck in the inlet to the rack. Something I didn’t notice before is there is a check valve in the inlet to the rack and the piece of metal had lodged in the check valve. I’m not sure if this was the issue with the rack but it more than likely added to the issues. When I took the rack off I turned it by hand and it had hard spots in the travel so it appears there where internal issues also. The new rack is smooth and operates as it should when turned lock to lock.

I had to install a fine mesh around the return fitting in the reservoir to keep the returning fluid from creating a vortex at the outlet of the reservoir and feeding air to the pump, it also helps with removing air from the fluid.

I’ve flushed the system a couple times and the fluid is clean now so hopefully I’ve gotten all the contaminants out.

The Hydro-boost feels more like my Denali now and is not making any noise like before. I’m a little concerned about the backup reservoir on the Hydro-boost right now as it feels as if it works some times and not others. I may replace the Hydro-boost at a latter date to see if I can resolve the peddle kick back that happens every so often. The cause could be air remaining in the back up reservoir so I’ll give it a little time to bleed out before I replace the Hydro-boost.

I had a failed front brake caliper so I have to replace it before I can take a test drive. The steering is quiet now and has a smooth feel so I’m confident I have resolved the two main issues.

I’m really interested in seeing how the reduced flow has affected the road feel of the rack.

I’ll post back when I get the car back on the road and complete the test drive.

Neal
 
Back
Top