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Messages - Jack Hidley

1
Suspension/Steering / Re: Steering rack upgrade
If you install a 15:1 steering rack on a car with a low volume PS pump, the problem is that if you turn the steering wheel fast enough, the pump will catch, because it can't supply enough fluid volume to the higher ratio steering rack. When this happens you will loose all PS assist. During normal driving, you will never have this problem. It will only show up when trying to turn the steering very quickly.
2
Suspension/Steering / Re: '88 Turbo Coupe optimizing the stock brakes?
The big problem with using Mustang brake hoses on a Thunderbird is that the Thunderbird is designed for more suspension travel, so the hoses are longer and/or routed differently. In particular this really applies to the rear center hose.

We do have rear caliper hoses which will fit on a Thunderbird TC. These are in the 1994-95 Mustang section.
6
Drivetrain Tech / Re: Deciphering Fox Axels
Who is responsible for editing the spreadsheet in post #11? It has some errors and missing information.

Axle should only be measured from the brake mounting  to the very tip of the inner end. This is the dimension that affects the trackwidth of the car. It is the dimension that Ford uses in all of its drawings. The graphic shows the dimension to go from the brake mounting  to the end of the splines. It should show this going to the end of the axle. The name should be changed from "Spline-" for C and F to "End-".

The correct dimension for the 1979-93 Mustang axles is 29.16", not 29.18".

The correct dimension for the 1994-98 Mustang axles is 29.91", not 29.97".

The correct dimension for the 1999-2004 Mustang axles is 30.63", not 30.69".

Once these dimensions are fixed, the dimension A will need to be fixed with the formula below. There should be significant figures added in some of the cases.

It should be noted in the document that the 1999-2004 Mustang axle housings have 14mm bolt holes for the RLCAs, instead of 12mm. This means that a custom RLCA would need to be used with 12mm crush sleeves at the chassis end and 14mm crush sleeves at the axle end for use of this housing in any Fox chassis or 1994-98 SN95 chassis.

I would also add a note that the total axle axle  to axle  dimension for any assembly is dimension C+F+0.75" for all assemblies listed. If the car has a 31 spline differential or any Torsen differential, add 0.125" to this dimension as the pin/block is 0.875" wide in these differentials. This measurement must be taken with both axles pushed into the housing. This enables one to accurately determine what length axle is installed in the housing as well as if the differential is 28 or 31 spline when using stock parts, without taking anything apart. This won't work well with many aftermarket axles, because their length tolerance is usually poor.

Most rear disc rotors have a 0.235" thick hat. Drums have a thickness of 0.060". If you measure with the brakes installed, 2X of these dimensions need to be subtracted from the measurement.
 


 

  
7
Drivetrain Tech / Re: 87 7.5inch to 8.8 inch swap
A second issue with using a 1999-2004 SN95 rear axle assembly into a Fox chassis car is that this axle assembly uses 14mm bolts for the RLCAs instead of 12mm. To install the axle assembly, you would need to assemble a set of  RLCAs with 12mm crush sleeves in one end and 14mm crush sleeves in the other end.

I really wish this BBS would allow a larger font size;)
8
Suspension/Steering / Re: Mevotech control arms
SN95 ball joints can be used with Fox spindles. The only issue is that you won't have a locking feature for the nut. If this worries you, install the nut with one or two drops of blue, NOT red Loctite.

You can't really compare the internal friction of different ball joints which are not installed in a car. What really matters is the friction level when the ball joint is loaded by the sprung weight of the car. The OEM SN95 ball joints are much better under these conditions than anything made by the aftermarket.  
9
Suspension/Steering / Re: 1998 sn95 Spindles on 87 tbird 5.0
It is impossible to fix the bumpsteer issue created by using 1996-2004 spindles on a car with a 1979-93 k-member, with a bumpsteer kit. A bumpsteer kit can only lower the outer tie rod. With this combination of parts, the outer tie rod needs to be inside the end of the steering arm (raised 1"). See the links below for more information.

https://forums.corral.net/forums/8565296-post36.html

https://www.maximummotorsports.com/Good-Handling-Is-Fun-Facts-Fiction-and-the-Myth-of-the-Mustang-Bumpsteer-Problem.aspx

 
10
Suspension/Steering / Re: 87 tbird to Sn95 front brake hose issue
All 1982-93 Mustangs have the same sized nut on the end of both front brake lines. All 1994-2004 Mustangs have different sized nuts on each side.

The several data points I have for Fox Thunderbirds is that both nuts are the same size as each other on both sides of the car. For a Thunderbird installing SN95 calipers, you will need to use the MMBK15F front hose kit. This will not need any adapters. 
11
Suspension/Steering / Re: Short or tall Pinion Rack?
1979-84.5 Mustangs had the rack mounted to the k-member with 16mm bolts. These steering racks came with bushings for 16mm bolts.

1984.5 to 2004 Mustangs all used 12mm bolts for this. So the racks had bushings with a smaller ID. You can swap the bushings between the racks.

All 1979-2004 manual racks use the same spline and diameter on the input shaft as a 1979-93 Mustang (and Fox Thunderbird) with PS. If you use an aftermarket manual rack with the long input shaft, this will put it in the same location as the stock PS rack does.   
13
Suspension/Steering / Panhard bar for 1988 Sport
To use Mustang rear dampers you must lower the car a lot. Over 2". Even then, the rear suspension will not have a lot of droop travel.

Stock Mustang springs will lower the T-Bird quite a bit and won't really be stiff enough. The T-Bird uses longer springs and has more static weight on the rear tires, so it needs springs longer than a Mustang and stiffer. We have a number of stiffer Mustang springs, but most of them are too short to work properly. To solve the length issue, we designed a new RLCA with an adjustable height spring perch that is higher.

http://www.maximummotorsports.com/1983-88-Thunderbird-C429.aspx
14
Suspension/Steering / Panhard bar for 1988 Sport
It fits, but you may need to modify the tailpipes to fit between the PHB chassis bracket and the fuel tank, due to the larger T-Bird fuel tank.

There is no need to cut off the bump stop brackets.
15
User Rides / My 85 TBird
Mr. Sass,

I don't think the Crown Vic rear calipers will create a major problem on your car. There do have larger pistons than what is ideal for your application. This creates two problems.

1) Increases the amount of rear brake bias. Most of this can be dealt with through the adjustment of the proportioning valve. Since your car is going to have a staggered tire setup, that helps compensate some also.

2) It will make the brake pedal have more travel and require less effort. As noted above this is being countered by the fact that that the pedal ratio in the car is to low. It could also be corrected with a different m/c diameter, but there are no other diameter m/c that will fit on the hydroboost unit.

With the pin on the pedal raised 0.75" I think it will be fine.